Added
goal Set.thy "(Union M = {}) = (! A : M. A = {})";
AddIffs [Union_empty_conv];
Good idea??
(* Title: Pure/install_pp.ML
ID: $Id$
Set up automatic toplevel pretty printing.
*)
install_pp (make_pp ["Theory", "theory"] pprint_theory);
install_pp (make_pp ["Thm", "thm"] pprint_thm);
install_pp (make_pp ["Thm", "cterm"] pprint_cterm);
install_pp (make_pp ["Thm", "ctyp"] pprint_ctyp);
install_pp (make_pp ["Sign", "sg"] Sign.pprint_sg);
install_pp (make_pp ["Syntax", "ast"] Syntax.pprint_ast);
install_pp (make_pp ["typ"] Syntax.simple_pprint_typ);