handle Type.TYPE_MATCH, not arbitrary exceptions via MATCH_TYPE variable;
clarified handle/raise wrt. Quotient_Info.NotFound -- avoid fragile unqualified NotFound depending on "open" scope;
added helpful comments;
(* Title: HOL/MicroJava/BV/Semilat.thy
Author: Gerwin Klein
Copyright 2003 TUM
*)
header {* Semilattices *}
(*<*)
theory Semilattices
imports Err Opt Product Listn
begin
end
(*>*)