doc-src/TutorialI/Misc/Plus.thy
author wenzelm
Wed, 18 Aug 2010 23:44:50 +0200
changeset 38479 e628da370072
parent 27015 f8537d69f514
permissions -rw-r--r--
more efficient Markup_Tree, based on branches sorted by quasi-order; renamed markup_node.scala to markup_tree.scala and classes/objects accordingly; Position.Range: produce actual Text.Range; Symbol.Index.decode: convert 1-based Isabelle offsets here; added static Command.range; simplified Command.markup; Document_Model.token_marker: flatten markup at most once; tuned;

(*<*)
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
(*>*)