Put in minimal simpset to avoid excessive simplification,
just as in revision 1.9 of HOL/indrule.ML
(* Title: Lattice.thy
ID: $Id$
Author: Markus Wenzel, TU Muenchen
Lattices are orders with binary (finitary) infima and suprema.
*)
Lattice = Order +
axclass
lattice < order
ex_inf "ALL x y. EX inf. is_inf x y inf"
ex_sup "ALL x y. EX sup. is_sup x y sup"
consts
"&&" :: "['a::lattice, 'a] => 'a" (infixl 70)
"||" :: "['a::lattice, 'a] => 'a" (infixl 65)
defs
inf_def "x && y == @inf. is_inf x y inf"
sup_def "x || y == @sup. is_sup x y sup"
end