doc-src/TutorialI/Rules/Tacticals.thy

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/doc-src/TutorialI/Rules/Tacticals.thy	Mon Jan 22 11:01:05 2001 +0100
@@ -0,0 +1,51 @@
+theory Tacticals = Main:
+
+text{*REPEAT*}
+lemma "\<lbrakk>(P\<longrightarrow>Q); (Q\<longrightarrow>R); (R\<longrightarrow>S); P\<rbrakk> \<Longrightarrow> S"
+apply (drule mp, assumption)
+apply (drule mp, assumption)
+apply (drule mp, assumption)
+apply (assumption)
+done
+
+lemma "\<lbrakk>(P\<longrightarrow>Q); (Q\<longrightarrow>R); (R\<longrightarrow>S); P\<rbrakk> \<Longrightarrow> S"
+by (drule mp, assumption)+
+
+text{*ORELSE with REPEAT*}
+lemma "\<lbrakk>(Q\<longrightarrow>R); (P\<longrightarrow>Q); x<#5\<longrightarrow>P;  Suc x < #5\<rbrakk> \<Longrightarrow> R" 
+by (drule mp, (assumption|arith))+
+
+text{*exercise: what's going on here?*}
+lemma "\<lbrakk>(P\<and>Q\<longrightarrow>R); (P\<longrightarrow>Q); P\<rbrakk> \<Longrightarrow> R"
+by (drule mp, intro?, assumption+)+
+
+text{*defer and prefer*}
+
+lemma "hard \<and> (P \<or> ~P) \<and> (Q\<longrightarrow>Q)"
+apply intro   --{* @{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 \<and> ok2 \<and> doubtful"
+apply intro   --{* @{subgoals[display,indent=0,margin=65]} *}
+prefer 3   --{* @{subgoals[display,indent=0,margin=65]} *}
+oops
+
+
+
+(*needed??*)
+
+lemma "(P\<or>Q) \<and> (R\<or>S) \<Longrightarrow> PP"
+apply elim
+oops
+
+lemma "((P\<or>Q) \<and> R) \<and> (Q \<and> (P\<or>S)) \<Longrightarrow> PP"
+apply (elim conjE)
+oops
+
+lemma "((P\<or>Q) \<and> R) \<and> (Q \<and> (P\<or>S)) \<Longrightarrow> PP"
+apply (erule conjE)+
+oops
+
+end