doc-src/TutorialI/Misc/arith3.thy

renamed // to / (which is what we want anyway) to avoid clash with the new
use of // for quotienting

(*<*)
theory arith3 = Main:;
(*>*)
lemma "n*n = n \\<Longrightarrow> n=0 \\<or> n=1";
(**)(*<*)
oops;
end
(*>*)