expand_if is now by default part of the simpset.
(* Title: CCL/Lazy/fix.thy
ID: $Id$
Author: Martin Coen
Copyright 1993 University of Cambridge
Tentative attempt at including fixed point induction.
Justified by Smith.
*)
Fix = Type +
consts
idgen :: "[i]=>i"
INCL :: "[i=>o]=>o"
rules
idgen_def
"idgen(f) == lam t. case(t,true,false,%x y.<f`x, f`y>,%u. lam x. f ` u(x))"
INCL_def "INCL(%x. P(x)) == (ALL f.(ALL n:Nat. P(f^n`bot)) --> P(fix(f)))"
po_INCL "INCL(%x. a(x) [= b(x))"
INCL_subst "INCL(P) ==> INCL(%x. P((g::i=>i)(x)))"
end