src/CCL/Hered.thy
changeset 0 a5a9c433f639
child 1149 5750eba8820d
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/CCL/Hered.thy	Thu Sep 16 12:20:38 1993 +0200
     1.3 @@ -0,0 +1,30 @@
     1.4 +(*  Title: 	CCL/hered.thy
     1.5 +    ID:         $Id$
     1.6 +    Author: 	Martin Coen
     1.7 +    Copyright   1993  University of Cambridge
     1.8 +
     1.9 +Hereditary Termination - cf. Martin Lo\"f
    1.10 +
    1.11 +Note that this is based on an untyped equality and so lam x.b(x) is only 
    1.12 +hereditarily terminating if ALL x.b(x) is.  Not so useful for functions!
    1.13 +
    1.14 +*)
    1.15 +
    1.16 +Hered = Type +
    1.17 +
    1.18 +consts
    1.19 +      (*** Predicates ***)
    1.20 +  HTTgen     ::       "i set => i set"
    1.21 +  HTT        ::       "i set"
    1.22 +
    1.23 +
    1.24 +rules
    1.25 +
    1.26 +  (*** Definitions of Hereditary Termination ***)
    1.27 +
    1.28 +  HTTgen_def 
    1.29 +  "HTTgen(R) == {t. t=true | t=false | (EX a b.t=<a,b>      & a : R & b : R) | \
    1.30 +\                                      (EX f.  t=lam x.f(x) & (ALL x.f(x) : R))}"
    1.31 +  HTT_def       "HTT == gfp(HTTgen)"
    1.32 +
    1.33 +end