src/Doc/Tutorial/Misc/Plus.thy
author wenzelm
Wed, 11 Nov 2020 21:00:14 +0100
changeset 72574 d892f6d66402
parent 67613 ce654b0e6d69
permissions -rw-r--r--
build documents in Isabelle/Scala, based on generated tex files as session exports; reworked "isabelle document" for quasi-offline document builds: similar functionality included in "isabelle build -o document=pdf";

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

text\<open>\noindent Define the following addition function\<close>

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

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

end
(*>*)