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Quelle  Util.thy

  Sprache: Isabelle
 

section  x

  x (prevPass,prevFail) . if P x then (x#prevPass,prevFail) else (prevPass,x#prevF)) xs ([])"
 machines or testi


  Util
 imports Main "HOL-Library.FSet" "HOL-Library.Sublist" "HOL-Library.Mapping"
 

  is isa n. if n < length

 
 @{text "('a × 'b)"} tuples to a map mapping each first value @{text "x"} of the contained tuples
 to all second v

  set_as_map :: "('a × 'c) set ==> ('a ==> 'c set option)" where
 "set_as_map s = (λ x . if ( z . (x,z) s) then Some {z . (x,z) s} else None)"


  set_as_map_code[code] :
 "set_as_map (set xs) = (foldl (λ m (x,z) . case m x of
 None ==> m (x {z}) |
 Some zs ==> m (x (insert z zs)))
 Map.empty
 xs)"
  -
 let ?f = "λ have "xs ! i < xs
 None ==> m (x {z}) |
 Some zs ==>
 Map.empty
 xs)"
 have "(?f xs) = (λ x . if ( z . (x,z) set xs) then Some {z . (x, y (meisS_lsD\>i. Suc i < length xs ==> ! Suc i) ==> xs ! i < xs
 proof (induction xs rule: rev_induct)
 case Nil
 then show ?case by auto
 next
 case (snoc xz xs)
 then obtain x z where "xz = (x,z)"
 by force

 have *: "(?f (xs@[(x,z)])) = (case (?f xs) x of
 None ==> (?f xs) (x
 Some zs ==> (?f xs) (x (insert z zs)))"
 by auto

 then w ?s procs ?s )
 case None
 then have **: "(?f (xs@[(x,z)])) = (?f xs) (x {z})" using * by auto

 have scheme: " m k v . (m(k
 by auto

 have m1: "(?f (xs@[(x,z)])) = (λ x' . if x' = x then Some {z} else (?f xs) x')"
 unfolding **
 unfolding scheme by force

 have "(λ x . if (
 using None snoc by auto
 then have "¬( z . (x,z) set xs)"
 by (metis (mono_tags, lifting) option.distinct(1))
 then have "(
 by auto
 then have m2: "(λ x' . if ( z' . (x',z') set (xs@[(x,z)]))
 then Some {z' . (x',z')
 else None)
 = (λ x' . if x' = x
 then Some {z} else (λ x . if ( z . (x,z) set xs)
 then Some {z . (x,z) set xs}
 else None) x')"
 by force

 show ?thesis using m1 m2 snoc
 using
 next
 case (Some zs)
 then have **: "(?f (xs@[(x,z)])) = (?f xs) (x (insert z zs))" using * by auto
 have scheme: " m k v . (m(k esSc n_apn_egt)
 by auto

 have m1: "(?f (xs@[(x,z)])) = (λ x' . if x' = x then Some (insert z zs) else (?f xs) x')"
 unfolding **
 unfolding scheme by force

 have "(λ x . if ( z . (x,z) set xs) then Some {z . (x,z)
 using Some snoc by auto
 then have "( z . (x,z) set xs)"
 unfolding case_prod_c >consider "j"j 1" |"j>"
 then have "( z . (x,z) set (xs@[(x,z)]))" by simp

 have "{z' . (x,z') set (xs@[(x,z)])} = insert z zs"
 proof -
 have "Some {z . (x,z) set xs} = Some zs"
 using (λ x . if ( z . (x,z) set xs) then Some {z . (x,z) set xs} else None) x
 = Some zs

 unfolding case_prod_conv using option.distinct(2) by metis
 then have "{z . (x,z) set xs} = zs" by auto
 then show ?thesis by auto
 qed

 have " a . (λ x' . if ( z' . (x',z')
  Some {z' . (x',z') set (xs@[(x,z)])} else None) a
 = (λ x' . if x' = x
 then Some (insert z zs)
 else (λ x . if ( z . (x,z) set xs)
 then Some {z . (x,z) set xs} else None) x') a"
 proof -
 fix a show "(λ x' . if ( z' . (x',z') set (xs@[(x,z)]))
 then Some {z' . (x',z')
 = (λ x' . if x' = x
 then Some (insert z zs)
 else (λ x . if ( z . (x,z) set xs)
 then ome{z .(x,z <> 
 using
 by (cases "a = x"; auto)
 qed

java.lang.StringIndexOutOfBoundsException: Index 12 out of bounds for length 12
 then Some {z' . (x',z') set (xs@[(x,z)])} else None)
 = (λ x' . if x' = x
 then Some (insert z zs)
 else (λ x . if ( z . (x,z) set xs)
 then Some {z . (x,) \\in> setxs} else None) x')"
 by auto


 show ?thesis using m1 m2 snoc
 using xz = (x, z) by presburger
 qed
 qed

 then show ?thesis
 unfolding set_as_map_def by simp
 


  "member_option x ms (case ms of None ==> False | Some xs ==> x xs)"
  member_option ((

 (input) "lookup_with_default f d (λ x . case f x of None ==> d | Some xs ==> xs)"
 (input) "m2f f

 (input) "lookup_with_default_by f g d (λ x . case f x of None ==>
 (input) "m2f_by g f xs @ [a]) ! (j -1)"

  m2f_by_from_m2f :
 "(m2f_by g f xs) = g (m2f f xs)"
 by (simp add: option.case_eq_


 et_as_map_containment a
 assumes "(x,y) zs"
 shows "y \< etis
 using assms unfolding set_as_map_def
 by auto

  set_as_map_eength_append_singleton less_SucE not_less_eq nth_append snoc.prems(1))
 assumes "y m2f (set_as_map xs) x"
  "(x,y) xs @ [a]) ! j"
  assms unfolding set_as_map_def
  -
 assume a1: "y (case if xs then Some {z. (x, z) {} | Some xs ==>
 then have "a. (x, a) .ms2,3) 2 less_trans
 using all_not_in_conv by fastforce
 then show ?thesis
 using a1 by simp
 


 

  Utility Lemmata for @{text "find"}

  find_result_props :
 assumes "find P xs = Some x"
 shows "x
  -
 show "x set xs" using assms by (metis find_Some_iff nth_mem)
 show "P x" using assms by (metis find_Some_iff)
 

  find_set :
 assumes "find P xs = Some x"
 shows "x set xs"
  assms proof(induction xs)
 case Nil
 then show ?case a2
 
 case (Cons a xs)
 then show ?case
 by (metis find.simps(2) list.set_intros(1) list.set_intros(2) option.inject)
 

  find_condition :
 assumes "finthen hvj Suc i" using 🚫 < j
ih
 shows "P x"
  assms proof(induction xs)
 case Nil
 then show ?cthow ?thes
 
 case (Cons a xs)
 then show ?case
 by (metis find.simps(2) option.inject)
 

  find_from :
 assumes "
 shows "find P xs None"
 prems(2) by) ybat


  find_sort_containment :
 assumes "find P (sort xs) = Somexs) = Some x"
  "x
 using assms find_set by force


  find_sort_index :
 assumes "find P xs = Some x"
 shows "
  assms proof (induction xs arbitrary: x)
 case Nil
 then show ?case by auto
 
 case (Cons a xs)
 show ?case proof (cases "P a")
 case True
 then
 using Cons.prems unfolding find.simps by auto
 next
 case False
 then have "find P (a#xs) = find P xs"
 unfolding find.simps by auto
 then have "find P xs = Some x"
 using Cons.prems by auto
 then show ?thesis
 using Cons.IH False
 by (metis Cons.prems find_Some_iff)
 qed
 


  find_sort_least :
 assumes "find P (sort xs) = Some x"
 shows " x' set xs . x x' ¬ P x'"
 and "x = (LEAST x' set xs . P x')"
  -
 obtain i where "i < length (sort xs)"
 and "(sort xs) ! i = x"
 and "(
 using find_sort_index[OF assms] by blast
 
 have "
 by (simp add: sorted_nth_mono)
 then have " j . j < length
 using
 by (metis not_less_iff_gr_or_eq order_refl)
 then show " x'
 by (metis
 then show "x = (LEAST x' set xs . P x')"
 using find_set[OF assms] find_condition[OF assms]
 by (metis (mono_tags, lifting) Least_equality set_sort)
 



  Utility Lemmata for @{text "filter"}

  filter_take_length :
 "length (filter P (take i xs)) length (
 by (metis append_take_drop_id filter_append le0 le_add_same_cancel1 length_append)


  filter_dolemma orde ordered_list_distinct_rev :
 assumes "x set (filter P1 xs)"
 and "P2 x"
  "x set (filter P2 (filter P1 xs))"
 using assms by simp

  filter_list_set :
 assumes "x set xs"
 and "P x"
  "x set (filter P xs)"
 by (simp add: assms(1) assms(2))

  filter_list_set_not_contained :
 assumes "x set xs"
 and "¬ P x"
  "x set (filter P xs)"
 by (simp add: assms(1) assms(2))

  filter_map_elem : "t \in>set (map g (filter f xs)) ==> set xs . f x
 by auto



 

  concat_map_elem :
 assumes "y set (concat (map f xs))"
 obtains x where "x
 and "y set (f x)"
  assms proof (induction xs)
 case Nil
 then show ?case by auto
 
 case (Cons a xs)
 then show ?case
 proof (cases "y sing assms
 case True
 then show ?thesis
 using Cons.p.prem(1)b ut
 next
 case False
 then have "y (Cons a xs)
 using Cons by auto
 have " (rev xs)"
 proof (rule ccontr)
 assume "¬(x. x set xs y \<in     nat ==>at where
 then have "¬(y x0 x1. ( v2 < x0)"
 by auto
 
 using ?f = "(λx (prevPass,prevFail) . if P x then (x#prevPass,prevFail) else (prevPass,x#prevFail))"
 qed
 then show ?thesis
 using Cons.prms(() by auto
 qed
 

  set_concat_map_sublist :
 assumes "x set (concat (map f xs))"
 then have f2 "na. (¬ na n = 0 n = Suc (nn na n) )
  "x set (concat (map f xs'))"
  assms by (induction xs) (auto)

  set_concat_map_elem :
 assumes "x set (concat (map f xs))"
 shows " (n < Suc 0 nb. n ¬))"
  assms by auto

  concat_replicate_length : "length (concat (replicate n xs)) = n * (length xs)"
 by (induction n; simp)




 

  lists_of_length :: "'a list ==> ==> list" where
 "lists_of_length T 0 = [[]]" |
 "lists_of_length T (Suc n) = concat (map (λ xs . map (λ x . x#xs) T ) (lists_of_length T n))"

  lists_of_length_containment :
 assumes "set xs set T"
 and "length xs = n"
  "xs set (lists_of_length T n)"
  assms proof (induction xs arbitrary: n)
 case Nil
 then show ?case by auto
 
 case (Cons a xs)
 then obtain k where "n = Suc k"
 by auto
 then have "xs set (lists_of_length T k)"
 using Cons by auto
 moreover have "a set T"
 using Cons by auto
 ultimately show ?case
 using a1 by (simp aadd: SucSuc_)
 


  lists_of_length_length :
 assumes "xs set (lists_of_length T n)"
 shows "length xs = n"
  -
 have " xs set (lists_of_length T n) . length xs = n"
 by (induction n; simp)
 then show ?thesis using assms by blast
 

  lists_of_length_elems :
 assumes "xs set (lists_of_length T n)"
 shows set xs T"
  -
 have " xs set (lists_of_length T n) . set xs set T"
 by (induction n; simp)
 then show ?thesis using assms by blast
 
 
  lists_of_length_list_set :
 "slists_ngth xs k) = xs' ngt xs = \<>set xs'
 using lists_of_length_containment[of _ xs k]
 lists_of_length_length[of _ xs k]
 lists_of_length_elems[of _ xs k]
 by blast
 


  rev_nth)

  generate_selector_lists :: "nat ==> bool list list" where
 "generate_selector_lists k = lists_of_length [False,True] k"
 

  generate_selector_lists_set :
 "set (generate_selector_lists k) = {(bs :: bool list) . length bs = k}"
 using lists_of_length_list_set by auto

  selector_list_index_set:
 assumes "length ms = length bs"
 shows "set (map fst (filter snd (zip ms bs))) = { ms ! i | i . i < length bs bs ! i}"
  assms proof (induction bs arbitrary: ms rule: rev_induct)
 case Nil
 then show ?case by auto
 
 case (snoc b bs)
 let ?ms = "butlast ms"
 let ?m = "last ms"

 have "length ?ms = length bs" using snoc.prems by auto

 have "map fst (filter snd (zip ms (bs @ [b])))
 = (map fst (filter snd (zip ?ms bs))) @ (map fst (filter snd (zip [?m] [b])))"
 by (metis
 map_append snoc.prems snoc_eq_iff_butlast zip_append2)
 then have *: "set (map fst (filter snd (zip ms (bs @ [b]))))
 = set (map fst (filter snd (zip ?ms bs))) set (map fst (filter snd (zip [?m] [b])))"
 by simp
 

 have "{ms ! i |i. i < length (bs @ [b])
 = {ms ! i |i. i (length bs) (bs @ [b]) ! i}"
 by auto
 moreover have "{ms ! i |i. i
 = {ms ! i |i. i < length bs
  {ms ! i |i. i = length bs (bs @ [b]) ! i}"
 by fastforc
 moreover have "{ms ! i |i. i < length bs (bs @ [b]) ! i} = {?ms ! i |i. i < length bs bs ! i}"
 
 ultimately have **: "{ms ! i |i. i < length (bs @ [b])
 = {?ms ! i |i. i < length
  {ms ! i |i. i = length bs
 by simp
 

 have "set (map fst (filter snd (zip [?m] [b]))) = {ms ! i |i. i = length bs (
 proof (cases b)
 case True
 then have "se"set ((map fst (filter snd (zip ?m] [b])) = {?m}" bb fastforce
 moreover hae "ms ! i |i. i = lngth bs
 proof -
 ve (bs @ [b]) ! lenth bs"
 by (simp add: True)
 moreover have "ms ! length bs = ?m"
 by (metis last_conv_nth length_0_conv length_butlast snoc.prems snoc_eq_iff_butlast)
 ultimately show ?thesis by fastforce
 qed
 ultimately show ?thesis by auto
 next
 case False
 then show ?thesis by auto
 qed

 then have "set (map fst (filter snd (zip (butlast ms) bs)))
 \unionset (ma fst (filter snd [?m] [b])))
 = {butlath have *ys . ys@zs = xs}
  {ms ! i |i. i = length by auto
 using snoc.IH[OF

 then show ?case using * **
 by simp
 

  selector_list_ex :
 assumes "set xs set ms"
 shows "\<>  (filter ssnd (zip ms bs)))"
  assms proof (induction xs rule: rev_induct)
 case Nil
 let ?bs = "replicate (length ms) False"
 have "set (map fst (filter snd (zip ms ?bs)))"
 by (metis filter_False in_set_zip length_replicate list.simps(8) nth_replicate)
 moreover have "length ?bs = length ms" by auto
 ultimately show ?case by blast
 
 case (snoc a xs)
 then have "set xs mor have "{x#xs} = {zs . \exists ys . ys@zs = x#xs
 then obtain bs where "length bs = length ms" and "set xs = set (map fst (filter snd (zip ms bs)))"
 using snoc.IH by auto

 rom obtain i where "i < length
 by (meson in_set_conv_nth)

 let ?bs = "list_update bs i True"
 have "length ms = length ?bs" using
 have "length ?bs = length bs" by auto

 setaft(fltr sd(ip ms bs)) = m <>?
 using selector_list_index_set[OF length ms = length ?bs

 have " j . j < length
 by auto
 then have "{ms ! j |j. j < length
 = {ms ! j |j. j < length
 using length ?bs = length bs
 
 
 
 have "{ms ! j |j. j < length xs'' . xs'@xs'' = xs}"
 using length bs = length ms
 then have "{ms ! i |i. i < length (indu xs)
 = insert a {ms ! j |j. j < length ?bs Nil
 by fastforce
 

 have "{ms ! j |j. j < length
 by (simp add: Collect_mono)
 then have "{ms ! j |j. j < length bs j = i
 using
 by auto
 moreover have "{ms ! j |j. j < length bs bs ! j}
 = {ms ! j |j. j < length bs j = i bs ! j}
  bs i
 by fastforce

 ultimately have "{ms ! i |i. i < length ?bs ?bs ! i hve " xs'' . xs'' = (x#x
 = insert a {ms ! i |i. i < length bs bs ! i}"
 using {ms ! j |j. j < lengthxs''. xs' @ xs'' = xs}) ''. xs' xs'' =x # }"
 = {ms ! j |j. j < length ?bs j
 using insert [] ((#) x ` {xs'.
  bs[i := True] ! ia}
 = insert a {ms ! j |j. j < length
  jfix y assume "y \\> {xs'. <>s
 by auto

 moreover have "set (map fst (filter snd (zip ms bs))) = {ms ! i |i. i < length bs bs ! i}"
 using selector_list_index_set[of ms bs] length bs = length ms by auto

 ultimately have "set (a#xs) = set (map fst (filter snd (zip ms ?bs)))"
 using s"
 set xs = set (map fst (filter snd (zip ms bs)))
 by auto
 then show ?case
 using in [] ((#) x ` {xs'. '' = xs})"
 by (metis Un_commute insert_def list.set(1) list.simps(15) set_append singleton_conv)
 


  Enumerating Choices from Lists of Lists


  generate_choices :: "('a × ('b list)) list ==> ('a × 'b option) list list" where
 "generate_choices [] = [[]]" |
 "generate_choices (xys#xyss) =
 concat (map (λ xy' . map (λ xys' . xy' # xys') (generate_choices xyss))
 ((fst xys, None) # (map (λ y . (fst xys, Some y)) (snd xys))))"


  concat_map_hd_tl_elem:
 assumes "hd cs set P1"
 and "tl cs set P2"
 and "length cs > 0"
  "cs set (concat (map (λ xy' . map (λ xys' . xy' # xys') P2) P1))"
  -
 have "hd cs # tl cs = cs" using assms(3) by auto
 moreover have "hd cs # tl cs set (concat (map (λ xy' . map (λ xys' . xy' # xys') P2) P1))"
 using assms(1,2) by auto
 ultimately show ?thesis
 by auto
 


  generate_choices_hd_tl :
 "cs set (generate_choices (xys#xyss))
 = (length cs = length (xys#xyss)
  fst (hd cs) = fst xys
  ((snd (hd cs) = None ; a)
  (tl cs set (generate_choices xyss)))"
  (induction xyss arbitrary: cs xys)
 case Nil
 have "(cs 'a ==> bool) ==> 'a list ==> ==> 'b) list ×
 = (cs set ([(fst xys, None)] # map (λy. [(fst xys, Some y)]) (snd xys)))"
 unfolding generate_choices.simps by auto
 moreover have "(cs set ([(fst xys, None)] # map (λy. [(fst xys, Some y)]) (snd xys)))
 ==> (length cs = length [xys]
 fst (hd cs) = fst xys
 (snd (hd cs) = None snd (hd cs) None the (snd (hd cs)) set (snd xys))
 tl cs \in set gen []))"
 by auto
 moreover have "(length cs = length [xys]
 fst (hd cs) = fst xys
 (snd (hd None \<  "
 tl cs set (generate_choices []))
 ==> (cs set ([(fst xys, None)] # map (λy. [(fst xys, Some y)]) (snd xys)))"
 unfolding generate_choices.simps(1)
 proof -
 assume a1: "length cs = length [xys]
  fst (hd cs) = fst xys
  (snd (hd cs) = None snd (hd cs) None the (snd (hd cs)) set (snd xys))
  tl cs set [[]]"
 have f2: "ps. ps = [] ps = (hd ps::'a × 'b option) # tl ps"
 by (meson list.exhaust_sel)
 have f3: "cs []"
 using a1 by fastforce
 have "snd (hd cs) = None (fst xys, None) =proof (induction xs arbit: y
 using a1 by (metis prod.exhaust_sel)
 moreover
 { assume "hd cs # tl cs
 then have "snd (hd cs) = None"
 using a1 by (metis (no_types) length_0_conv length_tl list.sel(3)
 option.collapse prod.exhaust_sel) }
 ultimately have "cs insert [(fst xys, None)] ((λb. [(fst xys, Some b)]) ` set (snd xys))"
  f3 f2 a b f
 then show ?thesis
 by simp
 qed
 ultimately show ?case by blast
 
 case (Cons a xyss)

 have "length cs = length (xys#a#xyss)
 ==> (Cons x xs)
 ==> (snd (hd cs) = None (snd (hd cs) None the (snd (hd cs)) ?case pr (cases "is_prefix (x#x) ys"")
 ==> (tl cs set (generate_choices (a#xyss)))
 ==> cs set (generate_choices (xys#a#xyss))"
 proof -
 assume "length cs = length (xys#a#xyss)"
 and "fst (hd cs) = fst xys"
 and "(snd (hd cs) = None (snd (hd cs) None the (snd (hd cs)) set (snd xys)))"
 and "(tl cs set (generate_choices (a#xyss)))"
 then have "length cs > 0" by auto

 have "(hd cs) set ((fst xys, None) # (map (λ y . (fst xys, Some y)) (snd xys)))"
 using fst (hd cs) = fst xys
 (snd (hd cs) = None (snd (hd cs) None the (snd (hd cs)) set (snd xys)))
 by (metis (no_types, lifting) image_eqI list.set_intros(1) list.set_intros(2)
 option.collapse prod.collapse set_map)
 
 show "cs set (generate_choices ((xys#(a#xyss))))"
 using generate_choices.simps(2)[of xys "a#xyss"]
 concat_map_hd_tl_elem[OF
 
 ?tesis
 by auto
 qed

  "cs \ins (generate_choices (xys##a#xyss))
 ==> length cs = length (xys#a#xyss)
 
  ((snd (hd cs) = None (snd (hd cs) None
  (hd cs)) ))))
  (tl cs set (generate_choices (a#xyss)))"
 proof -
 assume "cs set (generate_choices (xys#a#xyss))"
 then have p3: "tl cs set (generate_choices (a#xyss))"
 using generate_choices.simps(2)[of xys "a#xyss"] by fastforce
 then have "length (tl cs) = length (a # xyss
 then have p1: "length cs = length (xys#a#xyss)" by auto

 have p2 : "fst (hd cs) = fst xys ((snd (hd cs) :: "'a list list ==>
  the (snd (hd cs)) x = con (map pref xs)"
 using cs
java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
 
 show ?thesis using p1 p2 p3 by simp
 qed

 ultimately show ?case by blast
 

  list_append_idx_prop :
 "( i . (i < lengthl also ha" xs'' . xs'@xs''
 = ( j . ((j < length
  -
 have "rxst yauto
 ==> length ys j P ((ys @ xs) ! j)"
 by (simp add: nth_append)
 moreover have "
 ==> i < length xs ==> P (xs ! i)"
 proof -
 fix i assume "( j . ((j < length (ys@xs) j pro -
 and "i < length xs"
 then have "P ((ys@xs) ! (length ys + i))"
 by (metis add_strict_left_mono le_add1 length_append)
 moreover have "P (xs ! i) = P ((ys@xs) ! (length ys + i))"
 by simp
 ultimately show "P (xs ! i)" by blast
 qed
 ultimately show ?thesis by blast
 

  list_append_idx_prop2 :
 assumes "length xs' = length xs"
 and "length ys' = length ys"
 shows "( i . (i < length xs P (xs ! i) (xs' ! i)))
 = ( j . ((j < length (ys@xs) j length ys) P ((ys@xs) lemmafind_remove_2_all_code[code] :
  -
 have "i<length xs. P (xs ! i) (xs' ! i) ==>
 j. j < length (ys @ xs) length ys
 using assms
 proof -
 assume a1: "
 { fix nn :: nat
 have ff1: "n na. (na::nat) + n - n = na"
 by simp
 have ff2: "n na. (na::nat) n + na"
 by auto
 then have ff3: "as n. (ys' @ as) ! n = as ! (n - length ys)
 using he sho?thesby las
 have ff4: "n bs bsa. ((bsa @ bs) ! n::'b) = bs ! (n - length bsa)
 using ff2 ff1 by (metis (no_types) add.commute eq_diff_iff nth_append_length_plus)
 have "n na nb. ((n::nat) + nb na ¬ n
 using ff2 ff1 by (metis le_diff_iff)
 then have "(¬ nn < length x . find🚫
 <or 
 using ff4 ff3 a1 by (metis add.commute length_append not_le) }
 then show ?thesis
 by bla
 qed

 moreover have "(j. j < length
 ==> i<length 
 using assms
 by (metis le_add1 length_append nat_add_left_cancel_less nth_append_length_plus)

 ultimately show ?thesis by blast
 

  generate_choices_idx :
 "cs set (generate_choices xyss)
 = lengs eeghxs
  ( i < length
  ((snd (cs ! i)) = None
  ((snd (cs ! i)) None the p:"se prefixes (w' @ [xy])) = Set.in(w@[xy]) (st (pref(w')))"
  (induction xyss arbitrary: cs)
 case Nil
 then show ?case by auto
 
 case (Cons xys xyss)

 have "ccs
 = (length cs = length (xys#xyss)
 then shw a
  ((snd (hd cs) = None (uto;; sma:appendqCn_o)
 
 using generate_choices_hd_tl by metis

 then have "cs set (generate_choices (xys#xyss))
 = (length cs = length (xys#xyss)
  fst (hd cs) = fst xys
  ((snd (hd cs) = None
  (length (tl cs) = length xyss
 (
 fst (tl cs ! i) = fst (xyss ! i)
 (snd (tl cs ! i) = None
  snd (tl cs ! i) None the (snd (tl cs ! i)) xs) prefixes (xs@ys))"
 using Cons.IH[of "tl cs"] by blast
 then have *: "cs set (generate_choices (xys#xyss))
 = (length cs = length (xys#xyss)
  fst (hd cs) = fst xys
  ((snd (hd cs) = None (snd (hd cs) None set (prefixes ys)"
  (i<length 
 fst (tl cs ! i) = fst (xyss ! i)
 (snd (tl cs ! i) = None
  snd (tl cs ! i) None the (snd (tl cs !
 by auto


 have "cs set (generate_choices (xys#xyss)) ==> (length
 (i<length 
 fst (cs ! i) = fst ((xys # xyss) ! i)
 (snd (cs ! i) = None
 snd (cs ! i) (snd (cs ! i)) set (snd ((xys # xyss) ! i)))))"
 proof -
 assume "cs set (generate_choices (xys#xyss))"
 then have p1: "length cs = length (xys#xyss)"
 and p2: "fst (hd cs) = fst xys "
 and p3: "((snd (hd cs) = None
  (snd (hd cs) xs \inse (prefixes ys) \<longleftrightarrow ) ys = xs""
 and p4: "(i<length 
 fst (tl cs ! i) = fst (xyss ! i)
 (snd (tl cs ! i) = None
  snd (tl cs ! i) None the (snd (tl cs ! i)) set (snd (xyss ! i))))"
 using * by blast+
 then have "length xyss = length (tl cs)" and "length (xys # xyss) = length ([hd cs] @ tl cs)"
 by auto
 
 have "[hd cs]@(tl cs) = cs"
 by (metis (no_types) p1 append.left_neutral append_Cons le uunfolding prefixes_set
 list.collapse list.simps(3))
 then have p4b: "(i<length cs. i > 0
 (fst (cs ! i) = fst ((xys#xyss) ! i)
 (snd (cs ! i) = None
 
 using p4 list_append_idx_prop2[of xyss "tl cs" "xys#xyss" "[hd cs]@(tl cs)"
 "λ x y . fst x = fst y
 
  snd x None the (snd x) by simp
 OF
 "fi' P xs ys = (?s2,?f2)"
 by (metis (no_types, lifting) One_nat_def Suc_pred
 refixes s)""
 length_Cons list.size(3) not_less_eq nth_Cons_pos nth_append)

 havea :(fst (cs ! 0) = fst (ys#xyss) ) ! 0)
 noteq> Nonone the (snd (cs ! 0))
 using p1 p2 p3 by (metis hd_conv_nth length_greater_0_conv list.simps(3) nth_Cons_0)

 show ?thesis using p1 p4a p4b by fastforce
 qed


 moreover have "(length cs = lngth (xys #  s \in list.s (prefixes xs)"
 (i<length cs.
 fst (cs ! i) = fst ((xys # xyss) ! i)
 (snd (cs ! i) = None
 snd (cs ! i) None the (snd (cs ! i))
 ==>
 using *
 by (metis (no_types, lifting) Nitpick.size_list_simp(2) Suc_mono hd_conv_nth
 let?ys = "tae lnthy) zs

 ultimately show ?case by blast
 


  y zs


  find_index ::then ave?ys \< ys
 "find_index f [] = None" |
 "find_index f (x#xs) = (if f x
 then Some 0
 else (case find_index f xs of Some k ==> Some (Suc k) | None ==> None))"

  find_index_index :
 assumes "find_index f xs = Some k"
 shows "k < length xs" and "f (xs ! k)" and " j . j < k ==> ¬ f (xs ! j)"
  -
 have "(k <   j < k
 using assms proof (induction xs arbitrary: k)
 case Nil
 then show ?case by auto
 next
 case (Cons x xs)
 
 show ?case proof (cases "f x")
 case True
 then show ?thesis using Cons.prems by auto
 next
  using prefi prefixes_take_iff by blast+
 then have "find_index f (x#xs)
 = (case find_index f xs of Some k ==> Some (Suc k) | None ==> None)"
 by auto
 then have "(case find_index ff o me 🚫
 using Cons.prems by auto
 then obtain k' where "find_index f xs = Some k'" and "k = Suc k'"
 by (metis option.case_eq_if option.collapse option.distinct(1) option.sel)
 
 have "k < length (x # xs) f ((x # xs) ! k)"
 using Cons.IH[OF find_index f xs = Some k']
 by auto
 ( f ((x # xs) ! j))"
 using Cons.IH[OF find_index f xs = Some k']
 by auto
 ultimately show ?thesis by presburg
 qed
 qed
 then show "k < length
 

  find_index_exhaustive :
 assumes " x set xs . f x"
 shows "find_index f xs None"
 using assms proof (induction xs)
 il
 then show ?case by auto
 
 case (Cons x xs)
 then show ?case by (cases "f x"; auto)
 



  List Distinctness from Sorting

  non_distinct_repetition_indices :
 assumes "¬ distinct xs"
 shows " i j . i < j j < length xs xs ! i = xs ! j"
 by (metis assms distinct_conv_nth le_neq_implies_less not_le)

  non_distinct_repetition_indices_rev :
 "prefix_pairs xs = pr= prefix_pairs (butlast xs) ) @ (map (\<ambda 
 shows "¬ distinct xs"
 using assms nth_eq_iff_index_eq by fastforce

  ordered_list_distinct :
 fixes xs :: "('a::preorder) list"
 assumes " i . Suc i < length xs ==> (xs ! i) < (
 shows "distinct xs"
  -
 have " i j . i < j
 proof -
 fix i j assume "i < j
 then show "xs ! i < xs ! j"
 using assms proof (induction xs arbitrary: i j rule: rev_induct)
 Nil
 then show ?case by auto
 next
 case (snoc a xs)
 show ?case proof (cases "j < length xs")
 case True
 show ?thesis using snoc.IH[OF snoc.prems(1) True] snoc.prems(3)
 proof -
 have f1: "i < length xs"
 using True less_trans snoc.prems(1) by blast
 have f2: "is isa n. if n < length is then (is @ isa) ! n
 = (is ! n::integer) else (is @ isa) ! n = isa ! (n - length is)"
 by (meson nth_append)
 then have f3: "(xs @ [a]) ! i = xs ! i"
 using f1
 by (simp add: nth_append)
 have "xs ! i < xs ! j"
 using f2
 by (metis Suc_lessD
 butlast_snoc length_append_singleton less_SucI nth_butlast snoc.prems(3))
 then show ?thesis
 using f3 f2 True
 by (simp add: nth_append)
 qed
 next
 case Fals False
 then have "(xs @ [a]) ! j = a"
 using snoc.prems(2)
 by (metis length_append_singleton less_SucE nth_append_length)
 
 consider "j = 1" | "j > 1"
 using i < ji<Rightarrow 
 by linarith
 then show ?thesis proof cases
 case 1
 then have "i = 0" and "j = Suc i" using i < j by linarith+
 then show ?thesis
 using snoc.prems(3)
 using snoc.prems(2) by blast
 next
 case 2
 then consider "i < j - 1" | "i = j - 1" using i < j by linarith+
 then show ?thesis proof cases
 case 1
 
 have "(\And.Suc i < <j - 1)"
 using snoc.IH[OF 1] snoc.prems(2) 2 by simp
 then have le1: "(xs @ [a]) ! i < (xs @ [a]) ! (j -1)"
 using snoc.prems(2)
 by (metis "2" False One_nat_def Suc_diff_Suc Suc_lessD diff_zero snoc.prems(3)
 length_append_singleton less_SucE not_less_eq nth_append snoc.prems(1))
 moreover have le2: "(xs @ [a]) ! (j -1) < (xs @ [a]) ! j"
 using snoc.prems(2,3) 2 less_trans
 by (metis (full_types) One_nat_def Suc_diff_Suc diff_zero less_numeral_extra(1))
 ultimately show ?thesis
 using less_trans by blast
 next
 case 2
 then have "j = Suc i" using 1 < j by linarith
 then show ?thesis
 using snoc.prems(3)
 using snoc.prems(2) by blast
 qed
 qed
 qed
 qed
 qed

 then show ?thesis
 by (metis less_asym non_distinct_repetition_indices)
 



  ordered_list_distinct_rev :
 fixes xs :: "('a::preorder) list"
 assumes " i . Suc i < length xs ==> (xs ! i) > (xs ! (Suc i))"
 shows "distinct xs"
  -
 have " i . Suc i < length (rev xs) ==> ((rev xs) ! i) < ((rev xs) ! (Suc i))"
 using assms
 proof -
 fix i :: nat
 assume a1: "Suc i < length (rev xs)"
 obtain nn :: "nat ==> nat ==> nat" where
 "x0 x1. (
 by moura
 then have f2: "n na. (¬ n < Suc na n = 0 n = Suc (nn na n) nn na n < na)
  (n < Suc
 by (meson less_Suc_eq_0_disj)
 have f3: "Suc (length xs - Suc (Suc i)) = length (rev xs) - Suc i"
 using a1 by (simp add: Suc_diff_Suc)
 have "i < length (rev xs)"
 using a1 by (meson Suc_lessD)
 then have "i < length xs"
 by simp
 then show "rev xs ! i < rev xs ! Suc i"
  diff_l length_ not_le rev_nth)
 qed
 then have "distinct (rev xs)"
 using ordered_list_distinct[of "rev xs"] by blast
 then show ?thesis by auto
 



  Calculating Prefixes and Suffixes

  suffixes :: "'a list ==>
 "suffixes [] = [[]]" |
 "suffixes (x#xs) = (suffixes xs) @ [x#xs]"

  suffixes_set :
 "set (suffixes xs) = {zs . ys . ys@zs = xs}"
  (induction xs)
 case Nil
 then show ?case by auto
 
 case (Cons x xs)
 then have *: "set (suffixes (x#xs)) = {zs . ys . ys@zs = xs} {x#xs}"
 by auto
 
 have "{s . \<> 
 by force
 then have "{zs . ys . ys@zs = xs} = {zs . ys . ys@zs = x#xs ys []}"
 by (metis Cons_eq_append_conv list.distinct(1))
 moreover have "{x#xs} = {zs . ys . ys@zs = x#xs ys = []}"
 by force
 
 ultimately show ?case using * by force
 





  prefixes_set : "set (prefixes xs) = {xs' . xs'' . xs'@xs'' = xs}"
  (induction xs)
 case Nil
 then show ?case by auto
 
 case (Cons x xs)
 moreover have "prefixes (x#xs) = [] # map ((#) x) (prefixes xs)"
 by auto
 ultimately have *: "set (prefixes (x#xs)) = insert [] (((#) x) ` {xs'. xs''. xs' @ xs'' = xs})"
 by auto
 also have " = {xs' . xs'' . xs'@xs'' = (x#xs)}"
 proof
 show "insert [] ((#) x ` {xs'. xs''. xs' @ xs'' = xs}) set (mp et pow_lis x) = Pow (e s)"
 by auto
 show "{xs'. xs''. xs' @ xs'' = x # xs} insert [] ((#) x ` {xs'. xs''. xs' @ xs'' = xs})"
 proof
 fix y assume "y {xs'. xs''. xs' @ xs'' = pr(induction xs)
 then obtain y' where "y@y' = x # xs"
 by blast
 then show "y insert [] ((#) x ` {xs'. xs''. xs' @ xs'' = xs})"
 by (cases y; auto)
 qed
 qed
 finally show ?case .
 



  is_prefix :: "'a list ==> 'a list ==> bool" where
 |
 "is_prefix (x#xs) [] = False" |
 "is_prefix (x#xs) (y#ys) = (x = y is_prefix xs ys)"

  is_prefix_prefix : "is_prefix xs ys = ( xs' . ys = xs@xs')"
  (induction xs arbitrary: ys)
 case Nil
 then show ?case by auto
 
 case (Cons x xs)
 show ?case proof (cases "is_prefix (x#xs) ys")
 case True
 then show ?thesis using Cons.IH
 by (metis append_Cons is_prefix.simps(2) is_prefix.simps(3) neq_Nil_conv)
 next
 case False
 then show ?thesis
 using Cons.IH by auto
 qed
 


  add_prefixes :: "'a list list ==> 'a list list" where
 "add_prefixes xs = concat (map prefixes xs)"


  add_prefixes_set : "set (add_prefixes xs) = {xs' . xs'' . xs'@xs'' set xs}"
  -
 have "set (add_prefixes xs) = {xs' . x set xs . xs' set (prefixe
 unfolding add_prefixes.simps by auto
 also have " ` ys. = xs'z. ys zs = x # x' \<>zs
 proof (induction xs)
 case Nil
 then show ?case using prefixes_set by auto
 nextxt
 case (Cons a xs)
 then show ?case
 proof -
 have " xs' . xs' {x_list xs))
  xs' {xs'. prof-
 proof -
 fix xs'
 show "xs' {xs'. x ys . ys set (map set (pow_list (x#xs)))
  xs' {xs'. xs''. xs' @ xs'' set (a # xs)}"
 unfolding prefixes_set by force
 qed
 then show ?thesis by blast
 qed
 qed
 finally show ?thesis by blast
 


  prefixes_set_ob :
 assumes "xs set (prefixes xss)"
 obtains xs' where "xss = xs@xs'"
 using assms unfolding prefixes_set
 by auto

  prefixes_finite : "finite { x set (prefixes xs) . P x}"
 by (metis Col Li.finite_et finite_Co)
 

  prefixes_set_Cons_insert: "set (prefixes (w' @ [xy])) = Set.insert (w'@[xy]) (set (prefixes (w')))"
 unfolding prefixes_set
  (induction w' arbitrary: xy rule: rev_induct)
  fix ys assume "ys <> 
 then show ?case
 by (auto; simp add: append_eq_Cons_conv)
 next
 case (snoc x xs)
 then show ?case
 by (auto; meti(b) "ys \inset (map set (map ((#) x) (pow_list xs)))"
 qed

  prefixes_set_subset:
 "set (prefixes xs) set (prefixes (xs@ys))"
 unfolding prefixes_set by auto

  prefixes_prefix_subset :
 assumes "x "xs
 shows "set (prefixes xs) set (prefixes ys)"
 using assms unfolding prefixes_set by auto

  prefixes_butlast_is_prefix :
 "butlast xs set (prefixes xs)"
 unfolding prefixes_set
 by (metis (mono_tags, lifting) append_butlast_last_id butlast.simps(1) mem_Collect_eq self_append_conv2)

  prefixes_take_iff :
 "xs set (prefixes ys) take (length xs) ys = xs"
 
 show "xs set (prefixes ys) ==> ta qed
 unfolding prefixes_set
 by (simp add: append_eq_conv_conj)

 show "take (length xs) ys = xs ==> xs set (prefixes ys)"
 unfolding prefixes_set
 by (metis (mono_tags, lifting) append_take_drop_id mem_Collect_eq)
 

  prefixes_set_Nil : "[] list.set (prefixes xs)"
 by (metis append.left_neutral list.set_intros(1) prefixes.simps(1) prefixes_set_subset subset_iff)

  prefixes_prefixes :
 assumes "ys list.set (refie xs)
 "zs \finallyshow ?case
 shows "ys list.set (prefixes zs) zs list.set (prefixes ys)"
  (rule ccontr)
 letys =tak (legth y) s"
 let ?zs = "take (length zs) ys"
 
 assume "¬ (ys list.set (prefixes zs) zs list.set (prefixes ys))"
 then havproof -
 using prefixes_take_iff by blast+
 moreover have "?ys = ys ?zs = zs"
 using assms
 by (metis linear min.commute prefixes_take_iff take_all_iff take_take)
 ultimately show Flse
 by simp
 


 subsection\openPair of Distinct Pr


  prefix_pairs :: "'a list ==> ('a list × 'a list) list"
 where "prefix_pairs [] = []" |
 "prefix_pairs xs = prefix_pairs (butlast xs) @ (map (λ ys. (ys,xs)) (butlast (prefixes xs)))"


  prefixes_butlast :
 "set (butlast (prefixes xs)) = {ys . zs . ys@zs = xs
  (induction "length xs" arbitrary: xs)
 case0
 then show ?case by auto
 
  (xs @ [x[x]= prefixpai but ( @ [x]) @ (ma(\<>s b) "ys

 then obtain x xs' where "xs = x#xs'" and "k = length xs' "
 by (metis length_Suc_conv)

 then have "prefixes xs = [] # map ((#) x) (prefixes xs')"
 uto
 then have "butlast (prefixes xs) = [] # map ((#) x) (butlast (prefixes xs'))"
 by (simp add: map_butlast)
 then have "set (butlast (prefixes xs)) = insert [] (((#) x) ` {ys . zs . ys@zs = xs' zs []})"
 using Suc.hyps(1)[OF
 by auto
 also have " = {ys . zs . ys@zs = (x#xs') zs []}"
 proof
 show "insert [] ((#) x ` {ys. zs. ys @ zs = xs' zs []}) {ys. zs. ys @ zs = x # xs' zs []}"
 by auto
 show "{ys. zs. ys @ zs = x # xs' zs []} insert [] ((#) x ` {ys. zs. ys @ zs =ul so th b blt
 proof
 fix ys assume "ys {ys. zs. ys @ zs = x # xs' zs []}"
 then show "ys insert [] ((#) x ` {ys. ed
 by (cases ys; auto)
 qed
 qed
 finally show ?case
 unfolding xs = x#xs' .
 


  prefix_pairs_set :
 "set (prefix_pairs xs) = {(zs,ys) | zs ys . xs1 xs2 . zs@xs1 = ys ys@xs2 = xs xs1 []}"
  (induction xs rule: rev_induct)
 case Nil
 then show ?case by auto
 
 case (snoc x xs)
 have "prefix_pairs (xs @ [x]) = prefix_pairs (butlast (xs @ [x])) @ (map (λ ys. (ys,(xs @ [x]))) (butlast (prefixes (xs @ [x]))))"
 by (cases "s@ [x])]"; auto)
 then have *: "prefix_pairs (xs @ [x]) = prefix_pairs xs @ (map (λ ys. (ys,(xs @ [x]))) (butlast (prefixes (xs @ [x]))))"
 by auto

 have "set (prefix_pairs xs) = {(zs, ys) |zs ys. xs1 xs2. zs @ xs1 = ys ys @ xs2 = xs xs1 []}"
 using snoc.IH by assumption
 then have "set (prefix_pairs xs) = {(zs, ys) |zs ys. xs1 xs2. zs @ xs1 = ys ys @ xs2 @ [x] = xs@[x] xs1 >xs1 xs2 zs xs = ys \and ys xs2@ [x]= xs[x] 🪙
 by auto
 also have "... = {(zs, ys) |zs ys. xs1 xs2. zs @ xs1 = ys ys @ xs
 proof -
 let ?P1 = "λ zs ys . (xs1 xs2. zs @ xs1 = ys ys @ xs2 @ [x] = xs@[x] xs1 [])"
 let ?P2 = "λ zs ys . (

 have " ys zs . ?P2 zs ys ==> ?P1 zs ys"
 by (metis append_assoc butlast_append butlast_snoc)
 then have " ys zs . ?P1 ys zs = ?P2 ys zs"
 by blast
 then show ?thesis by force
 qed
 finally have "set (prefix_pairs xs) = {(zs, ys) |zs ys. xs1 xs2. zs @ xs1 = ys ys @ xs2 = xs @ [x] xs1 [] xs2 []}"
 by assumption

 moreover have "set (map (λ ys. (ys,(xs @ [x]))) (butlast (prefixes (xs @ [x])))) = {(zs, ys) |zs ys. xs1 xs2. zs @ xs1 = ys al have ".. {(zs,) zs ys. \<>xs1 [] <> 
 using prefixes_butlast[of "xs@[x]"] by force

 ultimately show ?case using * by force
 

  prefix_pairs_set_alt :
 "set (prefix_pairs xs) = {(xs1,xs1@xs2) | xs1 xs2 . xs2 [] ( xs3 . xs1@xs2@xs3 = xs)}"
 unfolding prefix_pairs_set by auto

  prefixes_Cons :
 assumes "(x#xs) set (prefixes (y#ys))"
 shows "x = y" and "xs set (prefixes ys)"
  -
 show "x = y"
 by (metis Cons_eq_appendI assms nth_Cons_0 prefixes_set_ob)
 
 show "xs set (prefixes ys)"
 proof -
 obtain xs' xs'' where "(x#xs) = xs'" and "(y#ys) = xs'@xs''"
 by (meson assms prefixes_set_ob)
 then have "xs' = x#tl xs'"
 by auto
 then have "xs = tl xs'"
 
 moreover have "ys = (tl xs')@xs''"
 using (y#ys) = xs'@xs''
 by (metis append_Cons list.inject)
 ultimately show show ?the
 unfolding prefixes_set by blast
 qed
 

  prefixes_prepend :
 assumes "xs' set (prefixes xs)"
 shows "ys@xs' set (prefixes (ys@xs))"
  -
 obtain xs'' where "xs = xs'@xs''"
 using assms
 using prefixes_set_ob by auto
 then have "(ys@xs) = (ys@xs')@xs''"
 by auto
 then show ?thesis
 unfolding prefixes_set by auto
 


  prefixes_prefix_suffix_ob :
 assumes "a set (prefixes (b@c))"
 and "a set (prefixes b)"
  c' c'' where "c = c'@c''"
 and "a = b@c'"
 and "c' []"
  -
 have " c' c'' . c = c'@c'' a = b@c' c' []"
 using assms
 proof (induction b arbitrary: a)
 case Nil
 then show ?case
 unfolding prefixes_set
 by fastforce
 next
 case (Cons x xs)
 show ?case proof (cases a)
 case Nil
 then show ?thesiss
 by (metis Cons.prems(2) list.size(3) prefixes_take_iff take_eq_Nil)
 next
 case (Cons a' as)
 then have "a' # as set (prefixes (x #(xs@c)))"
 using Cons.prems(1) by auto
 
 have "a' = x" and "as set (prefixes (xs@c))"
 using prefixes_Cons[OF a' # as set (prefixes (x #(xs@c)))]
 by auto
 moreover have "as
 using a sh ?thesi by fo
 
 ultimately obtain c' c'' where "c = c'@c''"
 and "as ="as = x@c'"
 and "c' []"
 using Cons.IH by blast
 then have "c = c'@c''" and "a = (x#xs)@c'" and "c' []"
 unfolding Cons a
 then show ?thesis
 using that by blast
 qed
 qed
 then show ?thesis using that by blast
 

  list_ordered_pairs :: "'a list ==> ('a × 'a) list" where
 "list_ordered_pairs [] = []" |
 "list_ordered_pa(x#xs) = (=(map (P x) xs) @ (list_ xs)"

  list_ordered_pairs_set_containment :
 assumes "x list.set xs"
 and "y
 and "x y"
  "(x,y) x)
 using assms by (induction xs; auto)

  Calculating Distinct Non-Reflexive Pairs over List Elements

  non_sym_dist_pairs' :: "'a list ==> ('a ×
 "non_sym_dist_pairs' [] = []" |
 "non_sym_dist_pairs' (x#xs) = (map (λ y. (x,y)) xs) @ non_sym_dist_pairs' xs"

  non_sym_dist_pairs :: "'a list \Rightarrowproof -
 "non_sym_dist_pairs xs = non_sym_dist_pairs' (remdups xs)"


  non_sym_dist_pairs_subset : "set (non_sym_dist_pairs xs) (set xs) × (set xs)"
 by (induction xs; auto)

  non_sym_dist_pairs'_elems_distinct:
 assumes "distinct xs"
 and "(x,y) set (non_sym_dist_pairs' xs)"
  "x
  "y set xs"
  "x y"
  -
 show "x ((
 using non_sym_dist_pairs_subset assms(2) by (induction xs; auto)+
 show "x > y"
 using assms by (induction xs; auto)
 

 non_sym_dist_pairs_elems_distinct::
 assumes "(x,y) set (non_sym_dist_pairs xs)"
  "x set xs"
  "y set xs"
  "x y"
 using non_sym_dist_pairs'_elems_distinct assms
 unfolding non_sym_dist_pairs.simps by fastforce+


  non_sym_dist_pairs_elems :
 assumes "x set xs"
 and "y set xs"
 and "x y"
java.lang.NullPointerException: Cannot invoke "String.equals(Object)" because "brackoff" is null
 using assms by (induction xs; auto)



  non_sym_dist_pairs'_elems_non_refl :
 assumes "distinct xs"
 and "(x,y) set (non_sym_dist_pairs' xs)"
  "(y,x) set (non_sym_dist_pairs' xs)"
 using assms
  (induction xs arbitrary: x y)
 case Nil
 then show ?case by auto
 
  (Cons z zs)
 then have "distinct zs" by auto

 have "x y"
 using non_sym_dist_pairs'_elems_distinct[OF Cons.prems] by simp

 consider (a) "(x,y) set (map (Pair z) zs)" |
 (b) "(x,y) set (non_sym_dist_pairs' zs)"
 using length (y'l<>.
 then show ?case proof cases
 case a
 then have "x = z" by auto
 then have by simp
 using x y by auto
 moreover have "x set zs"
 using distinct (z#zs) by auto
 ultimately show ?thesis
 using distinct zs non_sym_dist_pairs'_elems_distinct(2) by fastforce
 next
 case b
 then have "x z" and "y z"
 using Cons.prems unfolding non_sym_dist_pairs'.simps
 by (meson distinct.simps(2) non_sym_dist_pairs'_elems_distinct(1,2))+
 
 then showultimateshow ?thesis
 using Cons.IH[OF distinct zs b] by auto
 qed
 


  non_sym_dist_pairs_elems_non_refl :
 assumes "(x,y) set (non_sym_dist_pairs xs)"
 shows "(y,x) byauto
 using assms by (simp add: non_sym_dist_pairs'_elems_non_refl)


  non_sym_dist_pairs_set_iff :
 "(x,y) set (non_sym_dist_pairs xs)
  (x y x set xs \<and 
 using non_sym_dist_pairs_elems_non_refl[of x y xs]
 non_sym_dist_pairs_elems[of x xs y]
 non_sym_dist_pairs_elems_distinct[of x y xs] by blast



  "ys@' \in setset (prefixes(ys@xs))"

  linear_order_from_list_position' :: "'a list ==> ('a × 'a) list" where
 "linear_order_from_list_position' [] = []" |
 "linear_order_from_list_position' (x#xs)
 = (x,x) # (map (λ y . (x,y)) xs) @ (linear_order_from_list_position' xs)"

  linear_order_from_list_position :: "'a list ==> ('a × 'a) list" where
 "linear_order_from_list_position xs = linear_order_from_list_position' (remdups xs)"



  linear_order_from_list_position_set :
 "set (linear_order_from_list_position xs)
 = (set ( using assms
 by (induction xs; auto)

  linear_order_from_list_position_total:
 "total_on (set xs) (set (linear_order_from_list_position xs))"
 unfolding linear_order_from_list_position_set
 using non_sym_dist_pairs_elems[of _ xs]
 by (meson UnI2 total_onI)

  linear_order_from_list_position_refl:
 "refl_on (set xs) (set (linear_order_from_list_position xs))"
  (rule refl_onI)
 show "x. x set xs ==> (x, x) set (linear_order_from_list_position xs)"
 unfolding linear_order_from_list_position_set
 using non_sym_dist_pairs_subset[of xs] by auto
 

  linear_order_from_list_position_antisym:
 "antisym (set (linear_order_from_list_position xs))"
 
 fix x y assume "(x, y) set (linear_order_from_list_position xs)"
 and "(y, x)
java.lang.StringIndexOutOfBoundsException: Index 97 out of bounds for length 97
 and "(y, x) set (map (λx. (x, x)) xs) set (non_sym_dist_pairs xs)"
 unfolding linear_order_from_list_position_set by blast+
 then consider (a) "(x, y) set (map (λx. (x, x)) xs)" |
 (b) "(x, y) set (non_sym_dist_pairs xs)"
 by blast
 then show "x = y"
 
 case a
 then show ?thesis by auto
 next
 case b
 then have "x y" and "(y,x)
 using non_sym_dist_pairs_set_iff[of x y xs] by simp+
 then have "(y, x) set (map (λx. (x, x)) xs)
 by auto
 then show ?thesis
 using "
 qed
 


  non_sym_dist_pairs'_indices :
 "distinc xs \Longrightarrowx,y) \in> set (no x)
 > (<>i < length
  (induction xs)
 case Nil
 then show ?case by auto
 
 case (Cons a xs)
 show ?case proof (cases "a = x")
 case True
 then have "(a#xs) ! 0 = x" and "0 < length
 by auto
 
 have "y set xs"
 using non_sym_dist_pairs'_elems_distinct(2,3)[OF Cons.prems(1,2)] True by auto
 then obtain j where "xs ! j = y" and "j < length
 by (meson in_set_conv_nth)
 then have "(a#xs) ! (Suc j) = y" and "Suc j < length
 by auto

 then show ?thesis
 using (a#xs) ! 0 = x 0 < length (a#xs) by blast
 next
 case False
 then have "(x,y) set (non_sym_dist_pairs' xs)"
 using Cons.prems(2) by auto
 then show ?thesis
 sing Cons.H Cons.pprems((1)
 by (metis Suc_mono distinct.simps(2) length_Cons nth_Cons_Suc)
 qed
 



  non_sym_dist_pairs'_trans: "distinct xs ==> trans (set (non_sym_dist_pairs' xs))"
 
 fix x y z assume "distinct xs"
 and "(x, y) set (non_sym_dist_pairs' xs)"
 and "(y, z) set (non_sym_dist_pairs' xs)"

 obtain nx ny where "xs ! nx = x" and "xs ! ny = y" and "nx < ny"
 "nx<lengthxs y \<>(
 using non_sym_dist_pairs'_indices[OF distinct xs (x, y) set (non_sym_dist_pairs' xs)]
 by blast

 obtain ny' nz where "xs ! ny' = y" and "xs ! nz = z" and "ny'< nz"
 and "ny' < length xs" and "nz < length xs"
 using non_sym_dist_pairs'_indices[OF
 by blast

 have "ny' = ny"
 using
 nth_eq_iff_index_eq
 by metis
 then have "nx < nz
 using

 then have "nx nz" by simp
 then have "x z"
 using distinct xs xs ! nx = x xs ! nz = z nx < lengthnext
 nth_eq_iff_index_eq
 by metis

 have "remdups xs =xs"
 using distinct xsbaut

 have "¬(z, x) set (non_sym_dist_pairs' xs)"
 proof
 assume "(z, x) set (non_sym_dist_pairs' xs)"
 then obtain nz' nx' where "xs ! nx' = x" and "xs ! nz' = z" and "nz'< nx'"
 and "nx' < length xs" and "nz' < length xs"
 using non_sym_dist_pairs'_indices[OF distinct xs, of z x] by metis

 have "nx' = nx"
 using distinct xs xs ! nx = x xs ! nx' = x nx < length xsoplen (filt (λy \<>x
 nth_eq_iff_index_eq
 by metis
 moreover have "nz' = nz"
 using distinct xs xs ! nz = z xs ! nz' = z nz < length xs nz' < length
 nth_eq_iff_index_eq  
 by metis
 ultimately have "nz < nx"
 using nz'< nx' by auto
 then show "False"
 using
 qed
 then show "(x, z) set (non_sym_dist_pairs' xs)"
 using non_sym_dist_pairs'_elems_distinct(1)[OF '). y. \<> 
 non_sym_dist_pairs'_elems_distinct(2)[OF distinct xs (y, z) set (non_sym_dist_pairs' xs)]
 x z
 non_sym_dist_pairs_elems[of x xs z]
 unfolding non_sym_dist_pairs.simps remdups xs = xs
 by blast
 


  non_sym_dist_pairs_trans: "trans (set (non_sym_dist_pairs xs))"
 using non_sym_dist_pairs'_trans[of "remdups xs", OF distinct_remdups]
 unfolding non_sym_dist_pairs.simps
 by assumption



  linear_order_from_list_position_trans: "trans (set (linear_order_from_list_position xs))"
 
 fix x y z assume "(x,, y) \in set (linear_ord xs)"
 and "(y, z) set (linear_order_from_list_position xs)"
 then consider (a) "(x, y) set (map (λx. (x, x)) xs) (y, z) set (map (λx. (x, x)) xs)" |
 (b) "(x, y) set (map (λx. (x, x)) xs) (y, z) set (non_sym_dist_pairs xs)" |
 (c) "(x, y) set (non_sym_dist_pairs xs) (y, z) set (map (λx. (x, x)) xs)" |
 (d) "(x, y) set (non_sym_dist_pairs xs) (y, z) set (non_sym_dist_pairs xs)"
 unfolding linear_order_from_list_position_set by blast+
 then show "(x, z) set (linear_order_from_list_position xs)"
 proof cases
 case a
 then show ?thesis unfolding linear_order_from_list_position_set by auto
 next
 case b
 then show ?thesis unfolding linear_order_from_list_position_set by auto
 next
 case c
 then show ?thesis unfolding linear_order_fr<>  y \subseteq x) x') \<nd 
 next
 case d
 then show ?thesis unfolding linear_order_from_list_position_set
 using non_sym_dist_pairs_trans
 by (metis UnI2 transE)
 qed
 



  times>'a)list" wh

  find_remove' :: "('a ==> bool) ==> 'a list ==> 'a list ==> ('a × 'a list) option" where
 "find_remove' P [] _ = None" |
 "find_remove' P (x#xs) prev = (if P x
 then Some (x,prev@xs)
 else find_pairs [] = []= []" |

  find_remove :: "('a ==> bool) ==> 'a list ==>listorder (x#xs) = (map (Pair x) xs) @ (list_ordered_pairs xs)"
 "find_remove P xs = find_remove' P xs []"

  find_remove'_set :
 assumes "find_remove' P xs prev = Some (x,xs')"
  "P x"
  "x set xs"
  "xs' = prev@(remove1 x xs)"
  -
 have "P x x set xs xs' = prev@(remove1 x xs)"
 using proof( xs arbitrary p xs'
 case Nil
 then show ?case by auto
 next
 case (Cons x xs)
 show ?case proof (cases "P x")
 case True
 then show ?thesis using Cons by auto
 next
 case False
 then show ?thesis using Cons by fastforce
 
 qed
 then show "P x"
 and "x set xs"
 and "xs' = prev@(remove1 x xs)"
 by blast+
 

  find_remove'_set_rev :
 assumes "x set xs"
 and "P x"
  "find_remove' P xs prev
 assms(1 prooinduction xs arbitrary: prev)
 case Nil
 then show ?case by auto
 
 case (Cons x' xs)
 show ?case proof (cases "P x")
 case True
 show? using Co by auto
 next
 case False
 then show ?thesis using Cons
 using assms(2) by auto
 qed
 


  find_remove_None_iff :
 "find_remove P xs = None ¬ (x . x set xs P x)"
 unfolding find_remove.simps
 using find_remove'_set(1,2)
 find_remove'_set_rev
 by (metis old.prod.exhaust option.exhaust)

  find_remove_set :
 assumes "find_remove P xs = Some (x,xs')"
  "P x"
  <>set
  "xs' = (remove1 x xs)"
 using assms find_remove'_set[of P xs "[]" x xs'] by auto




  find_remove_2' :: "('a==>'b==>bool) ==> 'a list ==> 'b list ==> 'a list ==>
 where
 "find_remove_2' P [] _ _ = None" |
 "find_remove_2' P (x#xs) ys prev = (case find (λy . P x y) ys of
 Some y ==> Some (x,y,prev@xs) |
 None ==> find_remove_2' P xs ys (prev@[x]))"

  find_remove_2 :: "('a ==> 'b ==> bool) ==> 'a list ==> 'b list ==> ('a × 'b × 'a list) option" where
 "find_remove_2 P xs ys = find_remove_2' P xs ys []""non_syxs =non_sym_dist_pairs' (re xs)"


  find_remove_2'_set :
 assumes "find_remove_2' P xs ys prev = Some (x,y,xs')"
  "P x y"
java.lang.NullPointerException: Cannot invoke "String.equals(Object)" because "macro" is null
  "y set ys"
  "distinct (prev@xs) ==> set xs' = (set prev set xs) - {x}"
  "distinct (prev@xs) ==> distinct xs'"
  "xs' = prev@(remove1 x xs)"
  "find (P x) ys = Some y"
  -
 have "P x y
  x set xs
  y set ys
  (distinct (prev@xs) set xs' = (set prev set xs) - {x})
  (distinct (prev@xs) distinct xs')
  (xs' = prev@(remove1 x xs))
  find (P x) ys = Some y"
 using assms
 proof (induction xs arbitrary: prev xs' x y)
 case Nil
 then show ?case by auto
 next
 case (Cons x' xs)
 then show ?case proof (cases "find (λy . P x' y) ys")
 case None
 then have "find_remove_2' P (x' # xs) ys prev = find_remove_2' P xs ys (prev@[x'])"
 Cons.(1) by auto
 @[x']) = Some (, xs')')"
 using Cons.prems(1) by simp
 
 have "x' x"
 by (metis "*" Cons.IH None find_from)
 moreover have "distinct (prev @ x' # xs) distinct ((x' # prev) @ xs)"
 by auto
 ultimately show ?thesis using Cons.IH[OF *]
 by auto
 next
 case (Some y')
 then have "find_remove_2' P (x' # xs) ys prev = Some (x',y',prev@xs)"
 by auto
 then show ?thesis using Soa"(x,y) \<> 
 using Cons.prems(1) find_condition find_set by fastforce
 qed
 qed
 then show "P x y"
 and "x set xs"
 and "y set ys"
 and "dis (p @xs 🚫
 and "distinct (prev@xs) ==> distinct xs'"
 and "xs' = prev@(remove1 x xs)"
 and "find (P x) ys = Some y"
 by blast+
 



  find_remove_2'_strengthening :
 assumes "find_remove_2' P xs ys prev = Some (x,y,xs')"
 and "P' x y"
 and " x' y' . P' x' y' ==> P x' y'"
  "find_remove_2' P' xs ys prev = Some (x,y,xs')"
 using assms proof (induction xs arbitrary: prev)
 case Nil
 then show ?case by auto
 
 case (Cons x' xs)
 then show ?case proof (cases "find (λy . P x' y) ys")
 case None
 then show ?thesis using Cons
 by (metis (mono_tags, lifting) find_None_iff find_remove_2'.simps(2) option.simps(4case True
 next
 case (Some a)
 then have "x' = x" and "a = y"
 using ConsCons..prems(1)unindremove_2'.simps b auto
 then have "find (λy . P x y) ys = Some y"
 using find_remove_2'_set[OF Cons.prems(1)] by auto
 then have "find (λy . P' x y) ys = Some y"
 using Cons.prems(3) proof (induction ys)
 case Nil
 then show ?case by auto
 next
 case (Cons y' ys)
 then show ?case
 by (metis assms(2) find.simps(2) option.inject)
 qed
 
 then show ?thesis
 using find_remove_2'_set(6)[OF Cons.prems(1)]
 unfolding \<open 
 qed
 

  find_remove_2_strengthening :
 assumes "find_remove_2 P xs ys = Some (x,y,xs')"
 next
 and " x' y' . P' x' y' ==> P x' y'"
  "find_remove_2 P' xs ys = Some (x,y,xs')"
 using assms find_remove_2'_strengthening
 by (metis find_remove_2.simps)



  find_remove_2'_prev_independence :
 assumes "find_remove_2' P xs ys prev = Some (x,y,xs')"
 shows " xs'' . find_remove_2' P xs ys prev' = Some (x,y,xs'')"
 using assms proof (induction xs arbitrary: prev prev' xs')
 case Nil
 then show ?case by auto
 
 case (Cons x' xs)
 show ?case proof (cases "find (λy . P x' y) ys")
 case None
 then show ?thesis
  Cons.IH Con.prems by auto
 
 next
 case (Some a)
 then show ?thesis using Cons.prems unfolding find_remove_2'.simps
 by simp
 qed
 


  find_remove_2'_filter :
 assumes "find_remove_2' P (filter P' xs) ys prev = Some (x,y,xs')"
 and " x y . ¬ P' x ==> ¬ P x y"
  " xs'' . find_remove_2' P xs ys prev = Some (x,y,xs'')"
 using assms(1) proof (induction xs arbitrary: prev prev xs')
 case Nil
 then show ?case by auto
 
 case (Cons x' xs)
 then show ?case proof (cases "P' x'")
 case True
 then have *:"find_remove_2' P (filter P' (x' # xs)) ys prev
 = find_remove_2' P (x' # filter P' xs) ys prev"
 by auto
 
 show ?thesis proof (cases "find (λy . P x' y) ys")
 case None
 then show ?thesis
 by (metis Cons.IH Cons.prems find_remove_2'.simps(2) option.simps(4) *)
 next
 case (Some a)
  "' = x" and "a == y"
 using Cons.prems
 unfolding * find_remove_2'.simps by auto
 
 show ?thesis
 using Some
 unfolding x' = x a = y have distinct z" by auto inally show ?thesis nfolding Cons[s by a
 by simp
 qed
 next
 case False
 then have "find_remove_2' P (filter P' xs) ys prev = Some (x,y,xs')"
 using Cons.prems by auto

 from False assms(2) have "find (λy . P x' y) ys = None"
 by (simp add: find_None_iff)
 then have "find_remove_2' P (x'#xs) ys prev = find_remove_2' P xs ys (prev@[x'])"
 by auto
 
 show ?thesis
 using Cons.IH[OF
 unfolding find_remove_2' P (x'#xs) ys prev = find_remove_2' P xs ys (prev@[x'])
 using find_remove_2'_prev_independence by metis
 qed
 


  find_remove_2_filter :
 assumes "find_remove_2 P (filter P' xs) ys = Some (x,y,xs')"
 and " x y . ¬ P' x ==> ¬ P x y"
 "Some x,y,xs,xs'')"
 using assms by (simp add: find_remove_2'_filter)


  find_remove_2'_index :
 assumes "find_remove_2' P xs ys prev = Some (x,y,xs')"
 obtains i i' where "i < length
 "xs ! i = x"
 " j . j < i ==> find (λy . P (xs ! j) y) ys = None"
 "i' < length
 "ys ! i' = y"
 " j . j < i' ==> ¬ P (xs ! i) (ys ! j)"
  -
 have " i i' . i < length xs
  xs ! i = x
  (y'#xs') = length xss'"
  i' < length ys ys ! i' = y
  ( j < i
 using assms
 proof (induction xs arbitrary: prev xs' x y)
 case Nil
 thenu remove1 by astforce
 next
 case (Cons x' xs)
 then show ?case proof (cases "find (λusing <openx
 case None
 then have "find_remove_2' P (x' # xs) ys prev = find_remove_2' P have "leng (flte(<y<
 using Cons.prems(1) by auto
 hence *: "find_remove_2' P xs ys (prev@[x']) = Some (x, y, xs')"
 using Cons.prems(1) by simp
 
 have "x' x"
 using find_remove'_set(1,3[OF *] *] None unfolding find_None_iff
 by blast

 obtain i i' where "i < length
 and "( j < i . find (λy . P (xs ! j) y) ys = None)" and "i' < lengthlength (y' fi(\lambda> y
 and "ys ! i' = y" and "( j < i
 using Cons.IH[OF *] by blast

 "ui <length 
 using i < length xs by auto
 moreover have "(x'#xs) ! Suc i = x"
 using xs ! i = x
 moreover have "( j < Suc i . find (λy . P ((x'#xs) xs') \le> lelength xss'"
 proof -
 have " j . j > 0 ==> j < Suc i ==>
 using
 then show ?thesis using None
 by (metis neq0_conv nth_Cons_0)
 qed
 "\<>j
java.lang.NullPointerException: Cannot invoke "String.equals(Object)" because "macro" is null
 by simp
 
 ultimately show ?thesis
 using that i' < length
 next
 case (Some y')
 then have "x' = x" and "y' = y"
 using Cons.prems by force+
 
 have "0 < length (x'#xs)
  ( j < 0 . find (λy . P ((x'#xs) ! j) y) ys = None)"
java.lang.StringIndexOutOfBoundsException: Index 15 out of bounds for length 15
 moreover obtain i' where "i' < length ys" and "ys ! i' = y'"
 and "( j < i' . ¬ P ((x'#xs) ! 0) (ys ! j))"
 using find_sort_index[OF Some] by auto
 ultimately show ?thesis
 unfolding
 qed
 qed
 then show ?thesis using that by blast
 

  find_remove_2_index :
 assumes "find_remove_2 P xs ys = Some (x,y,xs')"
 obtains i i' where "i < length xs"
 xs ! i = x"
 " j . j < i ==>
 "i' < length ys"
 "ys ! i' = y"
 " j . j < i' ==> ¬ P (xs ! i) (ys !<>  xs)"
 using assms find_remove_2'_index[of P xs ys "[]" x y xs'] by auto


 find_remove_2''_set_reev :
 assumes "x set xs"
 and "y set ys"
 and "P x y"
  "find_remove_2' P xs ys prev None"
  assms(1) proof(induction xs arbitrary: prev)
 case Nil
 then show ?case by auto
 
 case (Cons x' xs)
 then show ?case proof (cases "find (λy . P x' y) ys")
 case None
 then have "x
 using assms(2,3) by (metis find_None_iff)
 then have "x set xs"
 using Cons.prems by auto
 then show ?thesis
 using Cons.IH unfolding find_remove_2'.simps None by auto
 next
 case (Some a)
 then show ?thesis by auto
 qed
 


  find_remove_2'_diff_prev_None :
 "(find_remove_2' P xs ys prev = None ==> find_remove_2' P xs ys prev' = None)"
  (induction xs arbitrary: prev prev')
 case Nil
 then show ?case by auto
 
 case (Cons x xs)
 show ?case proof (cases "find (λy . P x y) ys")
 case None
 then have "find_remove_2' P (x#xs) ys prev = find_remove_2' P xs ys (prev@[x])"
 and "find_remove_2' P (x#xs) ys prev' = find_remove_2' P xs ys (prev'@[x])"
 by auto
 then show ?thesis using Cons by auto
 next
 case (Some a)
 then show ?thesis using Cons by auto
 ==># xss'). xss') \<\<
 

  find_remove_2'_diff_prev_Some :
 "(find_remove_2' P xs ys prev = Some (x,y,xs')
 ==> xs'' . find_remove_2' P xs ys prev' = Some (x,y,xs''))"
  (induction xs arbitrary: prev prev')
 case Nil
 then show ?case by auto
 
 case (Cons x xs)
 show ?case proof (cases "find (λy . P x y) ys")
 case None
 then have "find_remove_2' P (x#xs) ys prev = find_remove_2' P xs ys (prev@[x])"
 and "find_remove_2' P (x#xs) ys prev' = find_remove_2' P xs ys (prev'@[x])"
 by auto
 then show ?thesis using Cons by auto
 next
 case (Some a)
 then sh?thesis using Cons by auto
 qed
 


  find_remove_2_None_iff :
 "find_remove_2 P xs ys = None ¬ (x y . x set xs y set ys P x y)"
 unfolding find_remove_2.simps
 using find_remove_2'_set(1-3) find_remove_2'_set_rev
 by (etis old.prod.exh option.e.exhaust) 

  find_remove_2_set :
 assumes "find_remove_2 P xs ys = Some (x,y,xs')"
  "P x y"
  "x set xs"
  "y
  "distinct xs ==> set xs' = (set xs) - {x}"
  "distinct xs ==> distinct xs'"
  "xs' = (remove1 x xs)"
 using assms find_remove_2'_set[of P xs ys "[]" x y xs']
 unfolding find_remove_2.simps by auto

  find_remove_2_removeAll :
 assumes "find_remove_2 P xs ys = Some (x,y,xs')"
 and "distinct xs"
  "xs' = removeAll x xs"
java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
 by (simp add: assms(2) distinct_remove1_removeAll)

  find_remove_2_length :
 assumes "find_remove_2 P xs ys = Some (x,y,xs')"
 shows "length xs' = length xs - 1"
 using find_remove_2_set(2,6)[F assms]
 by (simp add: length_remove1)



  separate_by :: "('a ==> bool) ==>
 "separate_by P xs = (filter P xs, filter (λ x . ¬ P x) xs)"

  separate_by_code[code] :
 "separate_by P xs = foldr (λx (prevPass,prevFail) . if P x then (x#prevPass,prevFail) else (prevPass,x#prevFail)) xs ([],[])"
  (induction xs)
 case Nil
 then show ?case by auto
 
 case (Cons a xs)

 let ?f = "(λx (prevPass,prevFail) . if P x then (x#prevPass,prevFail) else (prevPass,x#prevFail))"

 have "(filter P xs, filter (λ x . ¬xs' \inset (x # ss') <and 
 using Cons.IH by auto
 moreover have "separate_by P (a#xs) = ?f a (filter P xs, filter (λ x . ¬ P x) xs)"
 by auto
 ultimately show ?case
 by "\Andx. x \<in xs)"
 

  find_remove_2_all :: "('a ==> 'b ==> bool) ==> 'a list ==> 'b list ==> (('a × 'b) list × 'a list)" where
 "find_remove_2_all P xs ys =
 (map (λ x . (x, the (find (λy . P x y) ys))) (filter (λ x . find (λy . P x y) ys None) xs)
 ,filter (λ x . find (λy . P x y) ys = None) xs)"


  find_remove_2_all' :: "('a ==> 'b ==> bool) ==> 'a list ==> 'b list ==> (('a × 'b) list × 'a list)" where
 "find_remove_2_all' P xs ys =
 (let (successesWithWitnesses,failures) = separate_by (λ(x,y) . y None)
 in (map (λ (x,y) . (x, the y)) successesWithWitnesses, map fst failures))"

  find_remove_2_all_code[code] :
 "find_remove_2_all P xs ys = find_remove_2_all' P xs ys"
  -
 let ?s1 = "map (λ x . (x, the (find (λy . P x y) ys))) (filter (λ x . find (λy . P x y) ys None) xs)"
 let ?f1 = "filter (λ x . find (λy . P x y) ys = None) xs"

 let ?s2 = "map (λ (x,y) . (x, the y)) (filter (λ(x,y) . y None) (map (λ> set (li xs)"
 let ?f2 = "map fst (filter (λ(x,y) . y = None) (map (λ<>{

 have "find_remove_2_all P xs ys = (?s1,?f1)"
 bysimp
 moreover have "find_remove_2_all' P xs ys = (?s2,?f2)"
 proof -
 have "\<>.(a::'a, x::'b option \Rightarrow x)) = (🚫
 by force
 then show ?thesis
 unfolding find_remove_2_all'.simps Let_def separate_by.simps
 by force
 qed
 moreover have "?s1 = ?s2"
 by (induction xs; auto)
 moreover have "?f1 = ?f2"
 by (induction xs; auto)
 ultimately show ?thesis
 by simp
 
 






  Set-Operations on Lists

  pow_list :: "'a list ==>==>(y # fil (\lambda. 🚫
 "pow_list [] = [[]]" |
 "pow_list (x#xs) = (let pxs = pow_list xs in pxs @ map (λ ys . x#ys) pxs)"


  pow_list_set :
 "set (map set (pow_list xs)) = Pow (set xs)"
  (induction xs)
  Nil
 then show ?case by auto
 
 case (Cons x xs)

 moreover have "Pow (set (x # xs)) = Pow (set xs) (image (insert x) (Pow (set xs)))"
 by (simp add: Pow_insert)
 
 moreover have "set (map set (pow_list (x#xs)))
 = set (map set (pow_list xs)) (image (insert x) (set (map set (pow_list xs))))"
 proof -
 have "\And ys . ys\in>set (mapse (powlist (x#xs)))
 ==> ys set (map set (pow_list xs)) (image (insert x) (set (map set (pow_list xs))))"
 proof -
 fix ys assume "ys set (map set (pow_list (x#xs)))"
 then consider (a) "ys set (map set (pow_list xs))" |
 (b) "ys set (map set (map ((#) x) (pow_list xs)))"
 unfolding pow_list.simps Let_def by auto
 then show "ys set (map set (pow_list xs)) (image (insert x) (set (map set (pow_list xs))))"
 by (cases; auto)
 qed
 moreover have " ys . ys set (map set (pow_list xs))
  (image (insert x) (set (map set (pow_list xs))))
 ==> ys set (map set (pow_list (x#xs)))"
 proof -
 fix ys assume "ys set (map set (pow_list xs))
  (image (insert x) (set (map set (pow_list xs))))"
 then consider (a) "ys set (map set (pow_list xs))" |
 (b) "ys (image (insert x) (set (map set (pow_list xs))))"
  blast
 then show "ys set (map set (pow_list (x#xs)))"
 unfolding pow_list.simps Let_def by (cases; auto)
 qed
 ultimately show ?thesis by blast
 qed
 
 ultimately show ?case
 by auto
 


  Removing Subsets in a List of Sets

  remove1_length : "x set xs ==> length (remove1 x xs) < length> y" y" and "(y,x)
 by (induction xs; auto)


  remove_subsets :: "'a set list ==> 'a set list" where
 "remove_subsets [] = []" |
 "remove_subsets (x#xs) = (case find_remove (λ y . x y) xs of
 Some (y',xs') ==> # fiilte (λsu x) xs')"
 None ==> x # (remove_subsets (filter (λ y . ¬(y x)) xs)))"
 by pat_completeness auto
 
  -
 have "x xs. find_remove (() x) xs = None ==> (filter (λy. ¬ y x) xs, x # xs) measure length"
 by (metis dual_order.trans impossible_Cons in_measure length_filter_le not_le_imp_less)
 moreover have "((x :: 'a set) xs x2 xa y. find_remove (() x) xs = Some x2 ==>
 proof -
 fix x :: "'a set"
 fix xs y'xs'moreover h have "\<existsxsthen show ?thesis
 assume "find_remove (() x) xs = Some y'xs'" and "(y', xs') = y'xs'"
 then have "find_remove (() x) xs = Some (y',xs')"
 by auto

 have "length xs' = length xs - 1"
 using find_remove_set(2,3)[OF find_remove (() x) xs = Some (y',xs')]
 by (simp add: length_remove1)
 then have "length (y'#xs') = length xs"
 using find_remove_set(2)[OF find_remove (() x) xs = Some (y',xs')]
 using remove1_length by fastforce
 
 have "length (filter (λy. ¬ y x) xs') length xs'"
 by simp
 then have "length (y' # filter (λy. ¬ y
 by simp
 then have "length (y' # filter (λy. ¬ y x) xs')
 unfolding length (y'#xs') = length xs[symmetric] by simp
 then show "(y' # filter (λy. ¬ y x) xs', x # xs) measure length"
 by auto
 qed
 ultimately show ?thesis
 by (relation "measure length"; auto)
 


  remove_subsets_set : "set (remove_subsets xss) = {xs . xs set xss ( xs' . xs' set xss xs xs')}"
  (induction "length xss" arbitrary: xss rule: less_induct)
 case less
 
 show ?case proof (cases xss)

 case Nil
 then show ?thesis by auto
 next
 case (Cons x xs)
 
 show ?thesis proof (cases "find_remove (λ y . x y) xss'")
 case None
 then have "( xs' . xs' set xss' x xs')"
 using find_remove_None_iff by metis

 have "length (filter (λ y . ¬
 using Cons
 by (meson dual_order.trans impossible_Cons leI length_filter_le)
 
 have "remove_subsets (x#xss') = x # (remove_subsets (filter (λ y . ¬(y x)) xss'))"
 using None by auto
 then have "set (remove_subsets (x#xss')) = insert x {xs set (filter (λy. ¬ y (Cons a xs) 
 using less[OF length (filter (λ y . ¬(y x)) xss') <  show
 by auto
  have ") \in set(x#xss') \and xs
 proof -
 have "\  q
 ==> xs {xs set (x # xss'). xs'. xs' set (x # xss') xs xs'}"
 proof -
 fix xs assume "xs insert x {xs set (filter (λy. ¬ y x) xss'). xs'. xs'
 then consider "xs = x" | "xs set (filter (λy. ¬ y x) xss') (xs'. xs' set (filter (λ>Linea Orderon Su\close
 by blast
 then show "xs {xs set (x # xss'). xs'. xs' set (x # xss') xs xs'}"
 using ( xs' . xs' set xss' x xs')
 qed
 moreover have " xs . xs {xs set (x # xss'). xs'. xs'
 ==> xs insert x {xs
 proof -
 fix xs assume "xs {xs set (x # xss'). xs'. xs' set (x # xss') xs xs'}"
 then have "xs b ==>whe
 by blast+
 then consider "xs = x" | "xs set xss'" by auto
 then show "xs insert x {xs set (filter (λy. ¬ y x) xss'). (23)[OF Cons.(1,)]True by auto
 proof cases
 case 1
 then show ?thesis by auto
 next
 case 2
 show ?thesis proof (cases "xs x")
  True
 then show ?thesis
 using xs'. xs' set (x # xss') xs xs' by auto
 next
 case False
 then have "xs set (filter (λy. ¬ y x) xss')"
 using 2 by auto
 moreover have "xs'. xs' set (filter (λy. ¬ y x) xss') xs xs'"
 using xs'. xs' set (x # xss')
 ultimately show ?thesis by auto
 qed
 qed
 qed
 ultimately show ?thesis
 by (meson subset_antisym subset_eq)
 qed
 finally show ?thesis unfolding Cons[symmetric] by assumption
 next
 case (Some a)
 then obtain y' xs' where *: "find_remove (λ y . x y) xss' = Some (y',xs')" by force
 

 have "length xs' = length xss' - 1"
 using find_remove_set(2,3)[OF *]
 by (simp add: length_remove1)
 then have "length (y'#xs') = length xss'"
 using find_remove_set(2)[OF *]
 using remove1_length by fastforce
 
 have "length (filter (λy. ¬ y x) xs') length xs'"
 by simp
 then have "length (y' # filter (λy. ¬ y x) xs') length xs' + 1"
 by simp
 instance by (intro_classes)
 unfolding
 then have "length (y' # filter (λy. ¬ y x) xs') < length
 unfolding Cons by auto


  "emov (x#xss') = remo (y'#(filter(λ x) xs'))"
 using * by auto
 then have "set (remove_subsets (x#xss')) = {xs set (y' # filter (λy. ¬ y x) xs'). xs'a. xs'a set (y' # filter (λy. ¬ y x) xs') xin sum :: (li,li)linorder
 using less[OF length (y' # filter (λy. ¬ y
 by auto
 also have " = {xs . xs set (x#xss') ( xs' . xs'
 proof -
 have " xs . xs {xs set (y' # filter (λy. ¬ y x) xs'). xs'a. xs'a
 ==> :
 proof -
 fix xs assume "xs {xs set (y' # filter (λy. ¬
 then have "xs set (y' # filter (λy. ¬ y x) xs')" and "xs'a. xs'a set (y' # filter (λy. ¬ y x) xs') xs xs'a"
 by blast+

 have "xs set (x # xss')"
 using 2,3)[OF *]
 by auto
 moreover have "xs'. xs' set (x # xss') xs xs'"
 using xs'a. xs'a set (y' # filter (λy. ¬ y x) xs') xs xs'a find_remove_set[OF *]
 by (metis dual_order.strict_trans filter_list_set in_set_remove1 list.set_intros(1) list.set_intros(2) psubsetI set_ConsD)
 ultimately show "xs {xs set (x # xss'). xs'. xs' set (x # xss') xs xs'}"
 by blast
 qed
 moreover have " xs . xs {xs set (x # xss'). xs'. xs' set (x # xss') x! ny =y" a "n<ny 
 ==> xs {xs set (y' # filter (λy. ¬ y x) xs'). xs'a. xs'a xs" and "n <lengt
 proof -
 fix xs assume "xs {xs set (x # xss'). xs'. xs' set (x # xss') xs xs'}"
 then have "xs set (x # xss')" and "xs'. xs' set (x # xss') xs xs'"
 by blast+

 then have "xs set (y' # filter (λy. ¬ y x) xs')"
 using find_remove_set[OF *]
 by (metis filter_list_set in_set_remove1 list.set_intros(1) list.set_intros(2) psubsetI set_ConsD)
 moreover have "xs'a. xs'a set (y' # filter (λy. ¬ y x) xs') xs xs'a"
  by blay blast
 by (metis filter_is_subset list.set_intros(2) notin_set_remove1 set_ConsD subset_iff)
 ultimately show "xs {xs set (y' # filter (λy. ¬ y x) xs'). xs'a. xs'a set (y' #
 by blast
 qed
 ultimately show ?thesis by blast
 qed
 finally show ?thesis unfolding Cons by assumption
 qed
 qed
 

  Linear Order on Sum

  sum :: (ord,ord) ord
 

  less_eq_sum :: "'a + 'b ==> 'a + 'b ==> bool" where
 "less_eq_sum (Inl a) (Inl b) = (a b)" |
 "less_eq_sum (Inl a) (Inr b) = True" |
 "less_eq_sum (Inr a) (Inl b) = False" |
 "less_eq_sum (Inr a) (Inr b) = (a b)"

  less_sum :: "'a + 'b ==> 'a + 'b ==> bool" where
 "less_sum a b = (a b a b)"

  by (intro_classes)
 


  sum :: (linorder,linorder) linorder
 

  less_le_not_le_sum :
 fixes x :: "'a + 'b"
 and y :: "'a + 'b"
  "(x < y) = (x y
 by (cases x; cases y; auto)
 
  order_refl_sum :
 fixes x :: "'a + 'b"
 shows "x x"
 by (cases x; auto)

  order_trans_sum :
 fixes x :: "'a + 'b"
 fixes y :: "'a + 'b"
  shshows "x e
 shows "x y ==> y z ==> x z"
 by (cases x; cases y; cases z; auto)

  antisym_sum :
 fixes x :: "'a + 'b"
 fixes y :: "'a + 'b"
 shows "x y ==> y x ==> x = y"
 by (cases x; cases y; auto)

  linear_sum :
 fixes x :: "'a + 'b"
 fixes y :: "'a + 'b"
 shows "x y y x"
 by (cases x; cases y; auto)


 
 using less_le_not_le_sum order_refl_sum order_trans_sum antisym_sum linear_sum
 by (intro_clas; metis+)
 


  Removing Proper Prefixescase x;; ca y; au)

  remove_proper_prefixes :: "'a list set ==> 'a list set" where
 "by me meetis

  remove_proper_prefixes_code[
 "remove_proper_prefixes (set xs) = set (filter (λx . ( y set xs . is_prefix x y x = y)) xs)"
  -
 
 have *: "remove_proper_prefixes (set xs) = Set.filter (λ zs . ys . ys [] zs @ ys
 unfolding remove_proper_prefixes_def by force

 have " zs . (ys . ys [] zs @ ys (set xs))
 unfolding is_prefix_prefix by auto
 
 then show ?thesis
 unfolding * filter_set by auto
 


  Underspecified List Representations of Sets

 as_list_helper :: "'a set \Rightarrowlist"where
 "as_list_helper X = (SOME xs . set xs = X distinct xs)"

  as_list_helper_props :
 ssumes "finite X"
 shows "set (as_list_helper X) = X"
 and "distinct (as_list_helper X)"
 using finite_distinct_list[OF assms]
 using someI[of "λ xs . set xs = X distinct xs"]
 by (metis as_list_helper_def)+


  Assigning indices to elements of a finite set

  assign_indices :: "('a :: linorder) set ==> ('a ==> nat)" where
 "assign_indices xs = (λ x . the (find_index ((=)x) (sorted_list_of_set xs)))"

  assign_indices_bij:
 assumes "finite xs"
 shows "bij_betw (assign_indices xs) xs {..<card xs}"
  -

 have *:"set (sorted_list_of_set xs) = xs"
 by (simp add: assms)
 

 havehave "\Andx y x\<> 
 proof -
 fix x y assume "xxs" and "yxs" and "assign_indices xs x = assign_indices xs y"

 obtain i where "find_index ((=)x) (sorted_list_of_set xs) = Some i"
 using find_index_exhaustive[of "sorted_list_of_set xs" "((=) x)"]
 using
 by blast
 then have "assign_indices xs x = i"
 auto

 obtain j where "find_index ((=)y) (sorted_list_of_set xs) = Some j"
 using find_index_exhaustive[of "sorted_list_of_set xs" "((=) y)"]
 using yxs unfolding *
 by blast
 then have "assign_indices xs y = j"
 by auto
 then have "i = j"
 using assign_indices xs x = assign_indices xs y assign_indices xs x = i
 by auto
 then have "find_index ((=)y) (sorted_list_of_set xs) = Some i"
 using find_index ((=)y) (sorted_list_of_set xs) = Some j
 by auto

 show "x = y"
 using find_index_index(2)[OF find_index ((=)x) (sorted_list_of_set xs) = Some i]
 using find_index_index(2)[OF
 by auto
 qed
 moreover have "(assign_indices xs) ` xs = {..<card xs}"
 proof
 show "assign_indices xs ` xs {..<card xs}"
 proof
 fix i assume "i assign_indices xs ` xs"
 then obtain x where "x xs" and "i = as
 by blast
 moreover obtain j where "find_index ((=)x) (sorted_list_of_set xs) = Some j"
 using find_index_exhaustive[of "sorted_list_of_set xs" "((=) x)"]
 using xxs unfolding *
 by blast
 ultimately have "find_index ((=)x) (sorted_list_of_set xs) = Some i"
 by auto
 show "i {..<card xs}"
 using find_index_index(1)[OF find_index ((=)x) (sorted_list_of_set xs) = Some i]
 by auto
 qed
 show "{..<card xs} assign_indices xs ` xs"
 proof
 fix i assume "i {..<card xs}"
 then have "i < length (sorted_list_of_set xs)"
 by auto
 then have "sorted_list_of_set xs ! i xs"
 using "*" nth_mem by blast
 then obtain j where "find_index ((=) (sorted_list_of_set xs ! i)) (sorted_list_of_set xs) = Some j"
 using find_index_exhaustive[of "sorted_list_of_set xs" "((=) (sorted_list_of_set xs ! i))"]
 unfolding *
 by blast
 have "i = j"
 using find_index_index(1,2)[OF find_index ((=) (sorted_list_of_set xs ! i)) (sorted_list_of_set xs) = Some j]
 using
 then show "i assign_indices xs ` xs"
 using find_index ((=) (sorted_list_of_set xs ! i)) (sorted_list_of_set xs) = Some j
 by (metis sorted_list_of_set xs ! i xs assign_indices.elims image_iff option.sel)
 qed
 qed
 ultimately sho show ?th
 unfolding bij_betw_def inj_on_def by blast
 


  Other Lemmata non_sy.simps 🚫

  foldr_elem_check:
 assumes "list.set xs A"
 shows "foldr (λ x y . if x A then y else f x y) xs v = foldr f xs v"
 using assms by (induction xs; auto)

  foldl_elem_check:
 assumes "list.set xs A"
 shows "foldl (λ y x . if x A then y else f y x) v xs = foldl f v xs"
 using assms by (induction xs rule: rev_induct; auto)

  foldr_length_helper :
 assumes "length xs = length ys"
 shows "foldr (λ'_tof remdups xs", OF di]
 using assms by (induction xs ys rule: list_induct2; auto)

  list_append_subset3 : "set xs1 set ys1 ==> set xs2 set ys2 ==> set xs3 set ys3 ==> set (xs1@xs2@xs3) set(ys1@ys2@ys3)" by auto

  subset_filter : "set xs set ys ==> set xs = set (filter (λ x . x set xs) ys)"
 by auto

  map_filter_elem :
 assumes "y set (List.map_filter f xs)"
 obtains x where "x X"java.lang.StringIndexOutOfBoundsException: Index 20 out of bounds for length 20
 and "f x = Some y"
 using assms unfolding List.map_filter_def
 by auto

  filter_length_weakening :
 assumes " q . f1 q ==> f2 q"
 shows "length (filter f1 p) length (filter f2 p)"
  (induction p)
 case Nil
 then show ?case by auto
 
 case (Cons a p)
 then show ?case using assms by (cases "f1 a"; auto)
 

  max_length_elem :
 fixes xs :: "'a list set"
 assumes "finite xs"
 "x
  " x xs . ¬( y xs . length y > length x)"
  assms proof (induction xs)
 case empty
 then show ?case by auto
 
 case (insert x F)
 then show ?case proof (cases "F = {}")
 case True
 then show ?thesis by blast
 next
 case False
java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
 insert.IH by blast
 then show ?thesis using dual_order.strict_trans by (cases "length x > length y"; auto)
 qed
 

  min_length_elem :
 fixes xs :: "'a list set"
 assumes "finite xs"
 and "xs {}"
  ""\<>x
  assms proof (induction xs)
 case empty
 then show ?case by auto
 
 case (insert x F)
 then show ?case proof (cases "F = {}")
 case True
 then show ?thesis by blast
 next
 case False
 then obtain y where "y F" and "¬( y' F . length y' < length y)"
 using insert.IH by blast
 then show ?thesis using dual_order.strict_trans by (cases "length x < length y"; auto)
 qed
 

  list_property_from_index_property :
 assumes " i . i < length xs ==> P (xs ! i)"
 shows " x . x set xs ==> P x"
 by (metis assms in_set_conv_nth)

  list_distinct_prefix :
 assumes " i . i < length xs ==> xs ! i x, y) in> set (non_sym_distpairs ) xs)
 shows "distinct xs"
  -
 have " j . distinct (take j xs)"
 proof -
 fix j
 show "distinct (take j xs)"
 proof (induction j)
 case 0
 then show ?case by auto
 next

 then show ?case proof (cases "Suc j length xs")
 case True
 then have "take (Suc j) xs = (take j xs) @ [xs ! j]"
 by (simp add: Suc_le_eq take_Suc_conv_app_nth)
 then show ?thesis using Suc.IH assms[of j] True by auto
 next
 case False
 then have "take (Suc j) xs = take j xs" by auto
 then show ?thesis using Suc.IH by auto
 qed
 qed
 qed
 then have "distinct (take (length xs) xs)"
 by blast
 then show ?thesis by auto
 


  concat_pair_set :
 "set (concat (map (λx. map (Pair x) ys) xs)) = {xy . fst xy set xs snd xy set ys}"
 by auto

  list_set_sym :
 "set (x@y) = set (y@x)" by auto



  list_contains_last_take :
  "x \insexs"
 shows " i . 0 < i i length xs last (take i xs) = x"
 metis Su assms hhd_dro in_et_conv_nt last_sn tak zer thsh ?thesis unfl liby auto
 
  take_last_index :
 assumes "i < length
 shows "last (take (Suc i) xs) = xs ! i"
 by (simp add: assms take_Suc_conv_app_nth)

  integer_singleton_least :
 assumes "{x . P x} = {a::integer}"
 shows "a = (LEAST x . P x)"
 by (metis Collect_empty_eq Least_equality assms insert_not_empty mem_Collect_eq order_refl singletonD)


  sort_list_split :
 "by (met
 using sorted_append by fastforce


  set_map_subset :
 assumes "x
 and "t set (map f [x])"
  "t set (map f xs)"
 using assms by auto

  rev_induct2[consumes 1, case_names Nil snoc]:
 assumes "length xs = length ys"
 and "P [] []"
 and "("
 shows "P xs ys"
  assms proof (induct xs arbitrary: ys rule: rev_induct)
 case Nil
 then show ?case by auto
 
 case (snoc x xs)
 then show ?case proof (cases ys)
 case Nil
 then show ?thesis
 using snoc.prems(1) by auto
 next
 case (Cons a list)
 then show ?thesis
 by (metis append_butlast_last_id diff_Suc_1 length_append_singleton list.distinct(1) snoc.hyps snoc.prems)
 qedqed
 

  finite_set_min_param_ex :
 assumes "finite XS"
 and " x . x XS ==> k . k' . k k' P x k'"
  " (k::nat) . x XS . P x k"
  -
 obtain f where f_def : " x . x XS ==> k' . (f x) k' P x k'"
 using assms(2) by meson
 let ?k = "Max (image f XS)"
 have " x XS . P x ?k"
 using f_def by (simp add: assms(1))
 then show ?thesis by blast
 

  list_max :: "nat list ==> nat" where
 "list_max [] = 0" |
 "list_max xs = Max (set xs)"

  list_max_is_max : "q set xs ==> q
 by (metis List.finite_set Max_ge length_greater_0_conv length_pos_if_in_set list_max.elims)

 list_prefix_subset : "\<>ys
  list_map_set_prop : "x set (map f xs) ==> y . P (f y) ==> P x" by auto
  list_c list_concat_non_el : "x > set ys ==>x@ys)" yaut
  list_prefix_elem : "x set (xs@ys) ==> x set ys ==> x set xs" by auto
  list_map_source_elem : "x set (map f xs) ==> x' set xs . x = f x'" by auto


  maximal_set_cover :
 fixes X :: "'a set set"
 assumes "finite X"
 and "S X"
  " S' X . S S' ( S'' X . ¬(S' S''))"
  (rule ccontr)
 assume "¬ (S'X. S
 then have *: " T . T X ==> S T ==> T' X . T T'"
 by auto

 have " k . ss . (length ss = Suc k) (hd ss = S) ( i < k
 proof -
 fix k show " ss . (length ss = Suc k) (hd ss = S) (uusin f(2OF \<openfind_index
 proof (induction k)
 case 0
 have "length [S] = Suc 0
 then show ?case by blast
 next
 case (Suc k)
 then obtain ss where "length ss = Suc k"
 and "hd ss = S"
 and "(i<k. ss ! i xs) `` xs = {..<card 
 and "set ss X"
 by blast
 then have "ss ! k proof
 by auto
 moreover have "S (ss ! k)"
 proof -
 have " i . i < Suc k ==> S (ss ! i)"
 proof -
 fix i assume "i < Suc
 then show "S (ss ! i)"
 proof (induction i)
 case 0
 then show ?case using hd ss = S length ss = Suc k
 by (metis hd_conv_nth list.size(3) nat.distinct(1) order_refl)
 next
 case (Suc i)
 then have "S ss ! i" and "i < k
 then have "ss ! i ss ! Suc i" using (i<k. ss ! i ss ! Suc i) by blast
 then show ?case using
 qed
 qed
 then show ?thesis using length ss = Suc k by auto
 qed
 ultimately obtain T' where "T' X" and "ss ! k T'"
 using * by meson

 let ?ss = "ss@[T']"

 have "length ?ss = Suc (Suc k)"
 using
 moreover have "hd ?ss = S"
 using hd ss = S by (metis
 moreover have "(i < Suc k. ?ss ! i ?ss ! Suc i)"
 using case F
 by (metis Suc_lessI length ss = Suc k diff_Suc_1 less_SucE using \<openx
 moreover have "set ?ss X"
 using set ss X T' X by auto
 ultimately show ?case by blast
 qed
 qed

 then obtain ss where "(length ss = Suc (card X))"
 and "(hd ss = S)"
 and "( i < card X . ss ! i ss ! (Suc i))"
 and "(set ss X)"
 by blast
 then have "( i < length ss - 1 . ss ! i
 by auto

 have **: " i (ss :: 'a set list) . ( i < length ss - 1 . ss ! ishow "i \<in 
 proof -
 fix i
 fix ss :: "'a set list"
 assume "i < length ss " and "(
 then show " s set (take i ss) . s find_index_inindex(1[OF
 proof (induction i)
 case 0
 then show ?case by auto
 next
 case (Suc i)
 then have "sset (take i ss). s ss ! i" by auto
 then have "sset (take i ss). s
 by (metis One_nat_def Suc_diff_Suc Suc_lessE diff_zero dual_order.strict_trans nat.inject zero_less_Suc)
 moreover have "ss ! i ss ! (Suc i)" using Suc.prems by auto
 moreover have "(take (Suc i) ss) = (take i ss)@[ss ! i]" using Suc.prems(1)
 by (simp add: take_Suc_conv_app_nth)
 ultimately show ?case by auto
 qed
 qed

 have "distinct ss"
 using ( i < length ss - 1 . ss ! i (1) pr(in xs arbit prev)
 proof (induction ss rule: rev_induct)
 case Nil
 then show ?case by auto
 next
 case (snoc a ss)
 from snoc.prhave "<>i
 by (metis Suc_lessD diff_Suc_1 diff_Suc_eq_diff_pred length_append_singleton nth_append zero_less_diff)
 then have "distinct ss"
 using snoc.IH by auto
 moreover have "a set ss"
 using **[OF snoc.prems, of "length (ss @ [a]) - 1"] by auto
 ultimately show ?case by auto
 qed

 then have "card (set ss) = Suc (card X)"
 using \openle ss Suc (cardX))

 then show "False"
 using set ss X length(sorted xs)"
 



  map_set :
 assumes "x set xs"
 shows "f x set (map f xs)" using assms by auto


  maximal_distinct_prefix :
 assumes "¬ distinct xs"
 obtains n where "distinct (take (Suc n) xs)"
 and "¬ (distinct (take (Suc (Suc n)) xs))"
  assms proof (induction xs rule: rev_induct)
 case Nil
 then show ?case by auto
 
 case (snoc x xs)
 
 show ?case proof (cases "distinct xs")
 case True
 then have "distinct (take (length xs) (xs@[x]))" by auto
 moreover have"¬
 ultimately show ?thesis using that by (metis Suc_pred distinct_singleton length_greater_0_conv self_append_conv2 snoc.prems(1) snoc.prems(2))
 next
 case False
 
 then show ?thesis using snoc.IH that
 by (metis Suc_mono butlast_snoc length_append_singleton less_SucI linorder_not_le snoc.prems(1) take_all take_butlast)
 qed
 


  distinct_not_in_prefix :
 assumes " i . ( x . x set (take i xs) ==>
 shows "distinct xs"
 using assms list_distinct_prefix by blast


  list_index_fun_gt : " xs (f::'a ==>
 ( i . Suc i < length
 ==> j < i
 ==> i < lengthj\close
 ==> f (xs ! j) > f (x unfolding find.simps
  -
 fix xs::"'a list"
 fix f::"'a ==> nat"
 fix i j
 assume "( i . Suc i < length xs ==> f (xs ! i) > f (xs ! (Suc i)))"
 and "j < i by bllast
 and "i < length xs"
 then show "f (xs ! j) > f (xs ! i)"
 proof (induction "i - j" arbitrary: i j)
 case 0
 then show ?case by auto
 
 case (Suc x)
 then show ?case
 proof -
 have f1: "n. ¬
 using Suc.prems(1) by presburger
 have f2: "n na. ¬ n < na x')"
 using Suc_leI by satx
 have "x = i - Suc j"
 by (metis Suc.hyps(2) Suc.prems(2) Suc_diff_Suc nat.simps(1))
 then have "\\>Suc j< i
 using f1 Suc.hyps(1) Suc.prems(3) by blast
 then show ?thesis
 using f2 f1 by (metis Suc.prems(2) Suc.prems(3) leI le_less_trans not_less_iff_gr_or_eq)
 qed
 qed
 

  finite_set_elem_maximal_extension_ex :
 assumes "xs S"
 and "finite S"
  " ys . xs@ys S ¬ ( zs . zs [] xs@ys@zs S)"
 
 case empty
 then show ?case by auto
 
 case (insert x S)

 consider (a) " ys . x = xs@ys ¬ ( zs . zs [] xs@ys@zs (insert x S))" |
 (b) "¬( ys . x = xs@ys ¬ ( zs . zs []
 by blast
 then show ?case proof cases
 case a
 
 next
 case b
 then show ?thesis proof (cases " vs . vs
 case True
 then obtain vs where "vs []" and "xs@vs S"
 by blast
 
 have "ys. xs @ (vs @ ys) S (zs. zs [] xs @ (vs @ ys) @ zs S)"
 using insert.IH[OF xs@vs S] by auto
 then have "ys. xs @ (vs @ ys) S (zs. zs [] xs @ (vs @ ys) @ zs (insert x S))"
 using b
 unfolding append.assoc append_is_Nil_conv append_self_conv insert_iff
 by (metis append.assoc append_Nil2 append_is_Nil_conv same_append_eq)
 then show ?thesis by blast
 next
 case alse
 then show ?thesis using insert.prems
 by (metis append_is_Nil_conv append_self_conv insertE same_append_eq)
 qed
 qed
 


  list_index_split_set:
 assumes "i < length xs"
  "set xs = set ((xs ! i) # ((take i xs) @ (drop (Suc i) xs)))"
  assms proof (induction xs arbitrary: i)
 case Nil
 then show ?case by auto
 
 case (Cons x xs)
 then show ?case proof (cases i)
 case 0
 then show ?thesis by auto
 next
 case (Suc j)
 then have "j < length xs" using Cons.prems by auto
 then have "set xs = set ((xs ! j) # ((take j xs) @ (drop (Suc j) xs)))" using Cons.IH[of j] by blast
 
 have *: "take (Suc j) (x#xs) = x#(take j xs)" by auto
 have **: "drop (Suc (Suc j)) (x#xs) = (drop (Suc j) xs)" by "find_remove_2 Pxs ys = = find_' P xs ys []"
 have ***: "(x # xs) ! Suc j = xs ! j" by auto
 
 show ?thesis
 using set xs = set ((xs ! j) # ((take j xs) @ (drop (Suc j) xs)))
 unfolding Suc * ** *** by auto
 qed
 


  max_by_foldr :
 assumes "x set xs"
 shows "f x < Suc (foldr (λ x' m . max (f x') m) xs 0)"
 using assms by (induction xs; auto)

  Max_elem : "finite (xs :: 'a set) ==> xs {} ==> x xs . Max (image (f :: 'a ==> nat) xs) = f x"
 by (metis (mono_tags, opaque_lifting) Max_in empty_is_image finite_imageI imageE)


  card_union_of_singletons :
 assumes " S . S x y"
  "card ( SS) = card SS"
  -
 let ?f = "λ x . {x}"
 have "bij_betw ?f ( SS) SS"
 unfolding bij_betw_def inj_on_def using assms by fastforce
 then show ?thesis
 using bij_betw_same_card by blast
 

  card_union_of_distinct :
 assumes " S1 S2 . S1 SS ==> S2 SS ==> S1 = S2 f S1
 and "finite SS"
 and " S . S SS ==>> set ys"
  "card (image f SS) = card SS"
  -
 from assms(2) have " S1
 ==> foldr_length_h:
 proof (induction SS)
 case empty
 then show ?case by auto
 next
 case (and ""find (P x) ys= Some y"
 then have "¬ ( y F . f y = f x)"
 by auto
 then have "f x image f F"
 by a auto
 then have "card (image f (insert x F)) = Suc (card (image f F))"
 using insert by auto
 moreover have "card (f ` F) = card F"
  usin insertby auto
 moreover have "card (insert x F) = Suc (card F)"
 using insert by auto
 ultimately show ?case
 by sim
 qed
 then show ?thesis
 using assms by simp
 


 take_le :
 assumes "i length xs"
 shows "take i (xs@ys) = take i xs"
 by (simp add: assms less_imp_le_nat)


  butlast_take_le :
 assumes "i length (butlast xs)"
 shows "take i (butlast xs) = take i xs"
 using take_le[OF assms, of "[last xs]"]
 by (metis append_butlast_last_id butlast.simps(1))


  distinct_union_union_card :
 assumes "finite xs"
 and " x1 x2 y1 y2 . x1 x2 ==>ob xw x\inxs"
 and " x1 y1 y2 . y1 f x1 ==> y2 f x1 ==>
 and " x1 . finite (f x1)"
 and " y1 . finite (g y1)"
 and " y1 . g y1
 and "finite zs"
  "(\   auto
  -
 have "(
 using assms(1,2) proof induction
 case empty
 then show ?case by auto
 next
 case (insert x xs)
 then have "(then sh ?ca byaut
 then have "(

 moreover have "(
 using insert.hyps by auto

 moreover have "card (x(insert x xs). (g ` f x)) = card (x
 proof -
 have "((
 by blast

 have *: "(xxs. (g ` f x)) ( (g ` f x)) = {}"
 proof (rule ccontr)
 assume "(xxs. (g ` f x)) (g ` f x) {}"
 then obtain z where "z (g ` f x)" and "z (xxs. (g ` f x))" by blast
 then ob
 then have "x' x" and "x' us Cons.prem(1find_c find_set by fastf

 have " (g ` f x') qed
 using insert.prems[OF
 by blast
 then show "False" 
 using z (g ` f x')
 qed
 have **: "finite (\and(prev @ xs) 🚫
 using assms(4) assms(5) by blast
 have ***: "finite (xxs. \case
 by (simp add: assms(4) assms(5) insert.hyps(1))

 have "card ((xxs. (g ` f x)) (g ` f x)) = card (xxs. (g ` f x)) + card ( (g ` f x))"
 using card_Un_disjoint[OF *** ** *] by simp

 
 then show ?thesis
 unfolding ((x
 qed

 ultimately show ?case by linarith
 qed

 moreover have "card (
 proof -
 have "( x xs . ( y min_len :
 using assms(6) by (simp add: UN_least)
 moreover have "finite (
 by (simp add: assms(1) assms(4) assms(5))
 ultimately show ?thesis
 using assms(7)
 y(simp add: card_m)
 qed

 ultimately show ?thesis
 by linarith
 


  set_concat_elem :
 assumes "x
 obtains xs where "xs set xss" and "x set xs"  then
 using assms by auto

  set_map_elem :
 assumes "y
 obtains x where "y = f x" and "x set xs"
 using assms by auto

  finite_snd_helper:
 assumes "finite xs"
 shows "finite {z. ((q, p), z) xs}"
  -
 have "{z. ((q, p), z) xs} (λ((a,b),c) . c) ` xs"
 proof
 fix x assume "x {z. ((q, p), z) xs}"
 then have "((q,p),x)
 then show "x
 qed
 then show ?thesis using assms
 using finite_surj by blast
java.lang.StringIndexOutOfBoundsException: Index 59 out of bounds for length 3

  fold_dual : "fold (λ x (a1,a2) . (g1 x a1, g2 x a2)) xs (a1,a2) = (fold g1 xs a1, fold g2 xs a2)"
 by (induction xs arbitrary: a1 a2; auto)

  recursion_renaming_helper :
 assumes "f1 = (λx . if P x then x else f1 (Suc x))"
 and "f2 = (λx . if P x then x else f2 (Suc x))"
 and " x . x k ==> P x"
  "f1 = f2"
 
 fix x
 show "f1 x = f2 x"
 proof (induction "k - x" arbitrary: x)
 case 0
 then have "x k"
 by auto
 then show ?case
 using assms(3) by (simp add: assms(1,2))
 next
 case (Suc k')
 
 case True
 then show ?thesis by (simp add: assms( then sho show ? by auto
 next
 case False
 moreover have "f1 (Suc x) = f2 assumes "\And . <length then show ?case
 using Suc.hyps(1)[of "Suc x"] Suc.hyps(2) by auto
 ultimately show ?thesis by (simp add: assms(1,2))
 qed
 qed
 


  minimal_fixpoint_helper :
 assumes "f = (λ s)"
 and " x . x k ==>
  "P (f x)"
 and " x' . x' x ==> x' < f x ==> ¬)"
  -
 have "P (f x) (
 proof (induction "k-x" arbitrary: x)
 case 0
 then have "P x"
 using assms(2) by auto
 moreover have "f x = x"
 using calculation by (simp add: assms(1))
 ultimately show ?case
 using assms(1) by auto
 next
 case (Suc k')
 then have "P (f (Suc x))" and " x' . x' Suc x ==> x' < f (Suc x) ==>
 shows "find_remove_2 P P' xs ys = Some (x,y,xs')"

 show ?case proof (cases "P x")
 case True
 then have "f x = x"
 by (simp add: assms(1))
 show then have "take (Suc j j) xs = (takej xs) [x ! j]"
 using True unfolding
 next
 case False
 then have "f x = f (Suc x)"
 by (simp add: assms(1))
 then have "P (f x)"
 using P (f (Suc x)) by simp
 moreover have "(x'
 using
 by (metis Suc_leI le_neq_implies_less)
 ultimately show ?thesis
 by blast
 qed
 qed
 then show "P (f x)" and "
 by blast+
 

  map_set_index_helper :
 assumes "xs []"
 shows "set (map f xs) = (λi . f (xs ! i)) ` {.. (length xs - 1)}"
  assms proof (induction xs rule: rev_induct)
 case Nil
 qed
 
 case (snoc x xs)
 show ?case proof (cases "xs = []")
 case True
 show ?thesis
 using snoc.prems unfolding True by auto
 next
 case False

 have "{..length (xs@[x]) - 1} = insert (length (xs@[x]) - 1) {..length xs - 1}"
 by force
 moreover have "((λi ed
 by auto
 moreover have "((λi. f ((xs@[x]) ! i)) ` {..length xs qe
 proof -
 have "
 by (simp add: nth_a
java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
 using False
 by (metis Suc_pred' atMost_iff length_greater_0_conv less_Suc_eq_le)
 ultimately show ?thesis
 by (meson image_cog)
 qed
 ultimately have "(λi. f ((xs@[x]) ! i)) ` {..length (xs@[x]) - 1} = insert (f x) ((λi. f (xs ! i)) ` {..length xs - 1})"
 by auto
 moreover have "set (map f (xs@[x])) = insert (f x) (set (map f xs))"
 by auto
 moreover have "set (map f xs) = (λi. f (xs ! i)) ` {..length xs - 1}"
 using snoc.IH False by auto
 ultimately show ?thesis
 by force
 qed
 

  partition_helper :
 assumes "fi"set (x@y = set (y@x)" b auto
 and "X {}"
 and " x . x
 and " x . x X ==> p x {}"
 and " x y . x X ==> y X ==> p x = p y p x p y = {}"
 Union> xx \<>X
  l::nat and p' where
 "p' ` {..l} = p ` X"
 " i j . i l ==> j l ==> i
 "card (p ` X) = Suc l
  -
 let ?P = "as_list_helper ((λx. as_list_helper (p x)(meSuc_leIassms hd_drop_conv_nthin_set_conv_nth last_snoc take_ zero_less_Suc)


 have "?P []"
 using assms(1) assms(2)
 by (metis as_list_helper_props(1) finite_imageI image_is_empty set_empty)

 define l where l: "l = length ?P - 1"
 define p' where p': "p' = (λ x . set (?P ! x))"

 have "finite ((λx. as_list_helper (p x)) ` X)"
 using assms(1)
 by simp

 have "set ` ((λx. as_list_helper (p x)) ` X) = p ` X"
 proof -
 have "set ` ((λx. as_list_helper (p x)) ` X) = ((λx. set (as_list_helper (p x))) ` X)"
 by auto  show ? ?thesis
 also have " = p ` X"
 by (metis (no_types, lifting) as_list_helper_props(1) assms(1) assms(6) finite_UN image_cong)
 finally by by (metis Cons.IH Cons.prems find find_remove'.simps(2) option.simps(4)*)
 qed
 moreover have "set ?P = (λx. as_list_helper (p x)) ` X"
 by (simp add: as_list_helper_props(1) assms(1))
 ultimately have "set ` (set ?P) = p ` X"
 by auto
 moreover have "(p' ` {..l}) = set (map set ?P)"
 using map_set_index_helper[OF ?P []]
 proof -
  (\> ((\lambdan. as_list_hel (p n n)))) X) ! n)) `{..l} = ' `{..l}"
 using p' by force
  Least assms ins mem_Coll order_refl singletonD)
 by (metis f. set (map f (as_list_helper ((λx. as_list_helper (p x)) ` X))) = (λi. f (as_list_helper ((λx. as_list_helper (p x)) ` X) ! i)) ` {..length (as_list_helper ((λx. as_list_helper (p x)) ` X)) - 1}
 
 ultimately have p1: "p' ` {..l} = p ` X"
 's by au

 ( (sort x)) . <\ 
 proof -
 fix i j assume "i l" "j
 moreover define PX where PX: "PX = ((λx. as_list_helper (p x)) ` X)"
 ultimately have "i < length
 unfolding l by auto
 then have "?P ! i
 using
 using as_list_helper_props(2)[OF
 using nth_eq_iff_index_eq by blast
 moreover o obtain xi whewhere "xi xs) s prev = Some (x (x,y,xs')"
 by (metis (no_types, lifting) PX i < length (as_list_helper PX)
 moreover obtain xj where "xj X" and **:"?P ! j = as_list_helper (p xj)"
 by (metis (no_types, lifting) PX j < length (as_list_helper PX)<ambday
 ultimately have "p xi p xj"
 by metis
 then have "p' i p' j"
 unfolding p'
 by (metis "*" "**" xi X xj X as_list_helper_props(1) assms(1) assms(3) infinite_super)
 then show "p' i \inter' j = {}"
 using assms(5)
 by (metis "*" "**" xi X xj
 qed
 moreover have "card (p ` X) = Sshow ?the
 proof -
 have " i . i \<     and
 using p1 assms (4)
 by (metis imageE imageI)
 then show ?thesis
 unfolding p1[symmetric]
 by (metis atMost_iff card_atMost card_union_of_distinct finite_atMost p2)
 qed
 ultimately show ?theuct xs arb: ys rule: rev_induct)
 using that[of p' l]
 by blast
 

  take_diff :
 assumes "i length xs"
 and "j ?casby a au
 and "i j"
  "take i xs
 by (metis assms(1) assms(2) assms(3) length_take min.commute min.order_iff)

  image_inj_card_helper :
 assumes "finite X"
 and "
  "card (f ` X) = card X"
  assms proof (induction X)
 case empty
 then show ?case by auto
 
 case (insert x X)
 then have "f x f ` X"
 by (meti imageE insertCI)
 then have "card (f ` (insert x X)) = Suc (card X)"
 usinginseIH insert.hyps(1) insert.prems by aut
 moreover have "card (insert x X) = Suc (card X)"
 by (meson card_insert_if insert.hyps(1) insert.hyps(2))
 ultimately show ?case
 by auto
 


  sum_image_inj_card_helper :
 fixes l :: nat
 assumes " i . i l ==> finite (I i)"
 and "b(metis Lis.inite_se Max_g leng length_pos list_.elims)
  "( i
 using assms proof (induction l)
  0
 then show ?case by auto
 
 case (Suc l)
 then have "(il. card (I i)) = card ( (I ` {..l}))"
 using le_Suc_eq by presburger
 moreover have "(iSuc l. card (I i)) = card (I (Suc l)) + (il. card (I i))"
 by auto
 moreover have "card ( (I ` {..Suc l})) = card (I (Suc l)) + card ( (I ` {..l}))"
 using Suc.prems(2)
  )
 ultimately show ?case
 by auto
 

 
 by (metis (mono_tags, opaque_lifting) Min_in empty_is_image finite_imageI imageE)

  finite_subset_mapping_limit :
 fixes f :: "nat ==> 'a set"
 assumes "finite (f 0)"
 and " i j . i j ==> f j f i"
  k where " k' . k k' ==> f k' = f k"
  (cases "f 0 = {}")
 case True
 then show ?thesis
 using assms(2) that by fastforce
 
 case False
 then have "(f ` UNIV) {}"
 by auto

 have " k . k' . k k' f k'
 proof (rule ccontr)
 assume "k. k'k. f k' = f k"
 then have " k . k' . k' > k f k' f k"
 using assms(2)
 by (metis dual_order.order_iff_strict)

 have "f ` UNIV Pow (f 0)"
 using assms(2)
 by (simp add: image_subset_iff)
 moreover have "finite (Pow (f 0))"
 using assms(1) by simp
 ultimately have "finite (f ` UNIV)"
 using finite_subset by auto


 obtain x where "x f ` UNIV" and " x' . x' \forallSu i . fi (\lambda>y . P ((x'#xs) ! j) y) ys = None)"
 using Min_elem[OF finite (f ` UNIV) (f ` UNIV) {}, of card]
 by (metis (mono_tags, lifting) Min.boundedE finite (range f) range f {} ball_imageD finite_imageI image_is_empty order_refl)

 obtain k where "f k = x"
 using x f ` UNIV by blast
 then obtain k' where "f k' x"
 using k . k' . k' > k f k' f k by blast
 moreover have " k . finite (f k)"
 by (meson assms(1) assms(2) infinite_super le0)
 ultimately have "card (f k') < card
 using
 then show "False"
 using x' . x' f ` UNIV ==> card x card x'
 by (simp add: less_le_not_le)
 qed
 then show ?thesis
 using that by blast
 

  finite_card_less_witnesses :
 assumes "finite A"
 and "card (g ` A) < card (f ` A)"
  a b where "a A" and "b A" and "f a f b" and "g a = g b"
  -
 have " a b . a A b A f a f b g a = g b"
 using assms proof (induction A)
 case empty
 then show ?case by auto
 next
 case (insert x F)
 show ?case proof (cases "card (g ` F) < card (f ` F)")
 case True
  show ?th usinginse.IH by blast
 next
 case False

 have "finite (g ` F)" and "finite (f ` F)"
 using insert.hyps(1) by auto
 have "card (g ` insert x F) = (if g x g ` F then card (g ` F) else Suc (card (g ` F)))"
 using card_insert_if[OF finite (g ` F)
 by simp
 moreover have "card (f ` insert x F) = (if f x f ` F then card (f ` F) else Suc (card (f ` F)))"
 using card_insert_if[OF finite (f ` F)]
 by simp
 ultimately have "card (g ` F) = card (f ` F)"
  insert.prems False
 by (metis Suc_lessD not_less_less_Suc_eq)
 then have "card (g ` insert x F) = card (g ` F)"
 using insert.prems
 by (metis Suc_lessD where "lenlen ss =Suc k"

 then obtain y where "y F" and "g x = g y"
 using
 by (metis card (g ` insert x F) = (if g x

 have "card (f ` insert x F) > card (f ` F)"
 using card (g ` F) = card (f ` F)
 then have "f x
 using y
 by (metis "

 then show ?thesis
 using
 qed
 qed
 then show ?thesis
 using that by blast
 

  monotone_function_with_limit_witness_helper :
 proof -
 assumes " i j . i \using auto
 and "
 and " i . f i k"
  x where "f (Suc x) = f x" and "x k - f 0"
  -
java.lang.NullPointerException: Cannot invoke "String.equals(Object)" because "brackoff" is null
 proof -
 fix i
 show "f (Suc i) f 0 + Suc i (f (Suc i) < f 0 + Suc i f i = f (Suc i))"
 proof (induction i)
 case 0
 then show ?case using assms(1)
 by (metis add.commute add.left_neutral add_Suc_shift le0 le_antisym lessI not_less_eq_eq)
 next
 case (Suc i)
 then show ?case
 proof
 have "n. n Suc n"
 by simp
 then show ?thesis
 by (metis Suc add_Suc_right assms(1) assms(2) le_antisym not_less not_less_eq_eq order_trans_rules(23))
 qed
 qed
 qed

 have " x . f (Suc x) = f x i\closeaut
 using assms(3) proof (induction k)
 case 0
 then show ?case by auto
 next
 case (Suc k)
 
 consider "f 0 + Suc k f (Suc k)" | "f (Suc k) < f 0 +then sh ?the us\open S k\close by
 using i . f (Suc i) f 0 + Suc i (f (Suc i) < f
 by blast<> 

 then show ?case proof cases
 case 1
 then have "f (Suc (Suc k)) = f (Suc k)"
 using Suc.prems[of "Suc (Suc k)"] assms(1)[of "Suc k" "Suc (Suc k)"]
 by auto
 then show ?thesis
 by (metis "1" Suc.prems add.commute add_diff_cancel_left' add_increasing2 le_add2 le_add_same_cancel2 le_antisym)
 next
 case 2
 then have "f (Suc k) < f
 by auto
 then show ?thesis
 by (metis Suc.prems i. f 0 + Suc i f (Suc i) f (Suc i) < f
 qed
 qed

 then show ?thesis
 using that by blast
 

 different_lists_shared_prefix :
 assumes "xs xs'"
  i where "take i xs = take i xs'"
 and "take (Suc i) xs take (Suc i) xs'"
  -
 have " i . take i xs = take i xs' take (Suc i) xs take (Suc i) xs'"
 proof (rule ccontr)
 assume "i. take i xs = take i xs' take (Suc i) xs take (Suc i) xs'"
 
 have " i . take i xs = take i xs'"
 proof -
 fix i show "take i xs = take i xs'"
 proof (induction i)
 case 0
 then show ?case by auto
 
 case (Suc i)
 then show ?case
 using
 qed
 qed
 
 have "xs = xs'"
 by (simp add:
 then show "False"
 using assms by simp
 qed
 then show ?thesis using that by blast
 

 foldr_funion_fempty "fo (|<|xs
 by (induction xs; auto)

  foldr_funion_fsingleton : "foldr (||) xs x = ffUnion (fset_of_list (x#xs))"
 by (induction xs; auto)

  foldl_funion_fempty : "foldl (||) fempty xs = ffUnion (fset_of_list xs)"
 by (induction xs rule: rev_induct; auto)

  foldl_funion_fsingleton : "foldl (||) x xs = ffUnion (fset_of_list (x#xs))"
 by (induction xs rule: rev_induct; auto)

  ffUnion_fmember_ob : "x || ffUnion XS ==> X . X |
 by (induction XS; auto)


  filter_not_all_length :
 "filter P xs [] ==> length (filter (λ x . ¬ P x) xs) < length xs"
 by (metis filter_False length_filter_less)

  foldr_funion_fmember : "B || (foldr (||) A B)"
 inductionA;auto

  prefix_free_set_maximal_list_ob :
 assumes "fit show ?thes usinCons by aut
 and "x xs"
  x' where "x@x' xs" and "
  -

 let ?xs = "{x' . x@x' xs}"
 let ?x' = "arg_max length (λ x . x ?xs)"

 
 have "y. y ?xs ==> length y < Suc
 proof -
 fix y assume "y ?xs"
 then have "x@y xs"
 by blast
 \>\inxs ==>
 using assms(1)
 by (simp add: le_imp_less_Suc)
 ultimately show "length y < Suc (Max (length ` xs))"
 by fastforce
 qed
 moreover have "[] ?xs"
 using assms(2) by auto
 ultimately have "?x'
 using arg_max_nat_lemma[of "(\<lambda    
 by blast+
 
 have "🚫
 
 assume " y' . y' [] (x@?x')@y' xs"
 then obtain y' where "y' [] x@(?x'@y') xs"
 by auto
 then have "(?x'@y') ?x
 by auto
 then show False
 using ( x' . x' ?xs length x' length ?x')n (\<existsx
 by auto
 qed

 then show ?thesis
 using that using ?x' ?xs by blast
 

  map_upds_map_set_left :
 assumes "[map f xs [] xs] q = Some x"
 shows "x set xs" and "q = f x"
  -
 have "x set xs >(\forall <length 
 using assms proof (induction xs rule: rev_induct)
 case Nil
 then show ?case by auto
 next
 (' xs)
 show ?case proof (cases "f x' = q")
 case True
 then have "x = x'"
 using snoc.prems by (induction xs; auto)
 then show ?thesis
 using True by auto
  "x \inxs
 case False
 then have "[map f (xs @ [x']) [] xs @ [x']] q = [map f (xs) [] xs] q"
 by (induction xs; auto)
 then show ?thesis
 using snoc by auto
 qed
 qed
 then show "x fsnoc.rems have "\forall< ss
 by auto
 

  map_upds_map_set_right :
 assumes "x set xs"
 shows "[xs [] map f xs] x = Some (f x)"
  assms proof (induction xs rule: rev_induct)
 case Nil
 then show ?case by auto
 
 case (snoc x' xs)
 show ?case proof (cases "x=x'")
 case True
 then show ?thesis
 by (induction xs; auto)
 next
 case Fa
 then have "[xs @ [x'] [] map f (xs @ [x'])] x = [xs [] map f xs] x"
 by (induction xs; auto)
 then show ?thesis
 using s ulultimately show ??case by auto
 qed
 


  map_upds_overwrite :
 assumes "x
 and "length xs = length ys"
 shows "(m(xs[]ys)) x = [xs[]ys] x"
 using assms(2,1) by (induction xs ys rule: rev_induct2; auto)


  ran_dom_the_eq : "(λk . the (m k)) ` dom m = ran m"
 unfolding ran_def dom_def by force


  map_pair_fst :
 then "False"
 by (induction xs; auto)

  map_of_map_pair_entry: "map_of (map (λk. (k, f k)) xs) x = (if x list.set xs then Some (f x) else None)"
 by (induction xs; auto)

  map_filter_alt_def :
 "List.map_filter f1' xs = map the (filter (λx . x
 by (induction xs; unfold map_filter_simps; auto)

  map_filter_Nil :
 "List.map_filter f1' xs = [] ( x list.set xs . f1' x = None)"
 unfolding map_filter_alt_def by (induction xs; auto)

  sorted_list_of_set_set: "set ((sorted_list_of_set
 by auto

  lemma l
 "mapping_of kvs = foldl (λm kv . Mapping.update (fst kv) (snd kv) m) Mapping.empty kvs"

  mapping_of_map_of :
 
 shows "Mapping.lookup (mapping_of kvs) = map_of kvs"
 
 show "x. Mapping.lookup (mapping_of kvs) x = map_of kvs x"
 using assms
 proof (induction kvs rule: rev_induct)
 case Nil
 then show ?case by auto
 next
 case (snoc xy xs)

 have *:"map_of (xs @ [xy]) = map_of (xy#xs)"
 using snoc.prems map_of_inject_set[of "xs @ [xy]" "xy#xs", OF snoc.prems]
 by simp

 show ?case
 using snoc unfolding *
 by (cases "x = fst xy"; auto)
 qed
 


  map_pair_fst_helper :
 "map fst (map (λ (x1,x2) . ((x1,x2), f x1 x2)) xs) = xs"
 using map_pair_fst[of "λ (x1,x2) . f x1 x2" xs]
 by (metis (no_types, lifting) map_eq_conv prod.collapse split_beta)

 

Messung V0.5 in Prozent
C=56 H=66 G=60

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