doc-src/TutorialI/Misc/Plus.thy
author wenzelm
Fri, 03 Aug 2007 22:33:09 +0200
changeset 24150 ed724867099a
parent 19249 86c73395c99b
child 27015 f8537d69f514
permissions -rw-r--r--
sort indexes according to symbolic update_time (multithreading-safe);

(*<*)
theory Plus imports Main begin
(*>*)

text{*\noindent Define the following addition function *}

consts add :: "nat \<Rightarrow> nat \<Rightarrow> nat"
primrec
"add m 0 = m"
"add m (Suc n) = add (Suc m) n"

text{*\noindent and prove*}
(*<*)
lemma [simp]: "!m. add m n = m+n"
apply(induct_tac n)
by(auto)
(*>*)
lemma "add m n = m+n"
(*<*)
by(simp)

end
(*>*)