Myhill_2.thy
changeset 125 62925473bf6b
parent 120 c1f596c7f59e
child 128 6d2693c78c37
equal deleted inserted replaced
124:8233510cab6c 125:62925473bf6b
   300 
   300 
   301 definition 
   301 definition 
   302   tag_str_SEQ :: "lang \<Rightarrow> lang \<Rightarrow> string \<Rightarrow> (lang \<times> lang set)"
   302   tag_str_SEQ :: "lang \<Rightarrow> lang \<Rightarrow> string \<Rightarrow> (lang \<times> lang set)"
   303 where
   303 where
   304   "tag_str_SEQ L1 L2 \<equiv>
   304   "tag_str_SEQ L1 L2 \<equiv>
   305      (\<lambda>x. (\<approx>L1 `` {x}, {(\<approx>L2 `` {x - xa}) | xa.  xa \<le> x \<and> xa \<in> L1}))"
   305      (\<lambda>x. (\<approx>L1 `` {x}, {(\<approx>L2 `` {x - x'}) | x'.  x' \<le> x \<and> x' \<in> L1}))"
   306 
   306 
   307 text {* The following is a techical lemma which helps to split the @{text "x @ z \<in> L\<^isub>1 ;; L\<^isub>2"} mentioned above.*}
   307 text {* The following is a techical lemma which helps to split the @{text "x @ z \<in> L\<^isub>1 ;; L\<^isub>2"} mentioned above.*}
   308 
   308 
   309 lemma append_seq_elim:
   309 lemma append_seq_elim:
   310   assumes "x @ y \<in> L\<^isub>1 ;; L\<^isub>2"
   310   assumes "x @ y \<in> L\<^isub>1 ;; L\<^isub>2"