doc-src/TutorialI/Misc/Plus.thy
author wenzelm
Mon, 16 Mar 2009 23:52:30 +0100
changeset 30554 73f8bd5f0af8
parent 27015 f8537d69f514
permissions -rw-r--r--
substantial speedup of assumption and elim-resolution: Logic.assum_problems refrains from eager application of parameters, discriminate via Term.could_unify before invoking full unification (assumes terms in beta-normal form, as do higher term net operations anyway);

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

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

primrec add :: "nat \<Rightarrow> nat \<Rightarrow> nat" where
"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
(*>*)