(* Title: CCL/hered.thy
ID: $Id$
Author: Martin Coen
Copyright 1993 University of Cambridge
Hereditary Termination - cf. Martin Lo\"f
Note that this is based on an untyped equality and so lam x.b(x) is only
hereditarily terminating if ALL x.b(x) is. Not so useful for functions!
*)
Hered = Type +
consts
(*** Predicates ***)
HTTgen :: "i set => i set"
HTT :: "i set"
rules
(*** Definitions of Hereditary Termination ***)
HTTgen_def
"HTTgen(R) == {t. t=true | t=false | (EX a b.t=<a,b> & a : R & b : R) |
(EX f. t=lam x.f(x) & (ALL x.f(x) : R))}"
HTT_def "HTT == gfp(HTTgen)"
end