(* Title: HOLCF/Porder0.thy
ID: $Id$
Author: Franz Regensburger
Definition of class porder (partial order).
*)
Porder0 = Main +
(* introduce a (syntactic) class for the constant << *)
axclass sq_ord < type
(* characteristic constant << for po *)
consts
"<<" :: "['a,'a::sq_ord] => bool" (infixl 55)
syntax (xsymbols)
"op <<" :: "['a,'a::sq_ord] => bool" (infixl "\\<sqsubseteq>" 55)
axclass po < sq_ord
(* class axioms: *)
refl_less "x << x"
antisym_less "[|x << y; y << x |] ==> x = y"
trans_less "[|x << y; y << z |] ==> x << z"
end