src/FOL/ex/Classical.thy
changeset 61490 7c9c54eb9658
parent 61489 b8d375aee0df
child 62020 5d208fd2507d
equal deleted inserted replaced
61489:b8d375aee0df 61490:7c9c54eb9658
   320     \<longrightarrow> (\<forall>x. \<forall>y. q(x,y) \<longleftrightarrow> q(y,x))"
   320     \<longrightarrow> (\<forall>x. \<forall>y. q(x,y) \<longleftrightarrow> q(y,x))"
   321   by blast
   321   by blast
   322 
   322 
   323 text \<open>
   323 text \<open>
   324   Other proofs: Can use @{text auto}, which cheats by using rewriting!
   324   Other proofs: Can use @{text auto}, which cheats by using rewriting!
   325   Deepen_tac alone requires 253 secs.  Or
   325   @{text Deepen_tac} alone requires 253 secs.  Or
   326   by (mini_tac 1 THEN Deepen_tac 5 1)
   326   @{text \<open>by (mini_tac 1 THEN Deepen_tac 5 1)\<close>}.
   327 \<close>
   327 \<close>
   328 
   328 
   329 text\<open>44\<close>
   329 text\<open>44\<close>
   330 lemma
   330 lemma
   331   "(\<forall>x. f(x) \<longrightarrow> (\<exists>y. g(y) \<and> h(x,y) \<and> (\<exists>y. g(y) \<and> \<not> h(x,y)))) \<and>
   331   "(\<forall>x. f(x) \<longrightarrow> (\<exists>y. g(y) \<and> h(x,y) \<and> (\<exists>y. g(y) \<and> \<not> h(x,y)))) \<and>