theory Tacticals
imports Main
begin
text‹REPEAT
›
lemma "\P\Q; Q\R; R\S; P\ \ S"
apply (drule mp, assumption)
apply (drule mp, assumption)
apply (drule mp, assumption)
apply (assumption)
done
lemma "\P\Q; Q\R; R\S; P\ \ S"
by (drule mp, assumption)+
text‹ORELSE
with REPEAT
›
lemma "\Q\R; P\Q; x<5\P; Suc x < 5\ \ R"
by (drule mp, (assumption|arith))+
text‹exercise: what
's going on here?\
lemma "\P\Q\R; P\Q; P\ \ R"
by (drule mp, (intro conjI)?, assumption+)+
text‹defer and prefer›
lemma "hard \ (P \ ~P) \ (Q\Q)"
apply (intro conjI)
🍋 ‹@{subgoals[display,indent=0,margin=65]}
›
defer 1
🍋 ‹@{subgoals[display,indent=0,margin=65]}
›
apply blast+
🍋 ‹@{subgoals[display,indent=0,margin=65]}
›
oops
lemma "ok1 \ ok2 \ doubtful"
apply (intro conjI)
🍋 ‹@{subgoals[display,indent=0,margin=65]}
›
prefer 3
🍋 ‹@{subgoals[display,indent=0,margin=65]}
›
oops
lemma "bigsubgoal1 \ bigsubgoal2 \ bigsubgoal3 \ bigsubgoal4 \ bigsubgoal5 \ bigsubgoal6"
apply (intro conjI)
🍋 ‹@{subgoals[display,indent=0,margin=65]}
›
txt‹@{subgoals[display,indent=0,margin=65]}
A total of 6 subgoals...
›
oops
(*needed??*)
lemma "(P\Q) \ (R\S) \ PP"
apply (elim conjE disjE)
oops
lemma "((P\Q) \ R) \ (Q \ (P\S)) \ PP"
apply (elim conjE)
oops
lemma "((P\Q) \ R) \ (Q \ (P\S)) \ PP"
apply (erule conjE)+
oops
end
