src/HOL/Induct/Acc.thy
changeset 3120 c58423c20740
child 5102 8c782c25a11e
     1.1 --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
     1.2 +++ b/src/HOL/Induct/Acc.thy	Wed May 07 12:50:26 1997 +0200
     1.3 @@ -0,0 +1,26 @@
     1.4 +(*  Title:      HOL/ex/Acc.thy
     1.5 +    ID:         $Id$
     1.6 +    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
     1.7 +    Copyright   1994  University of Cambridge
     1.8 +
     1.9 +Inductive definition of acc(r)
    1.10 +
    1.11 +See Ch. Paulin-Mohring, Inductive Definitions in the System Coq.
    1.12 +Research Report 92-49, LIP, ENS Lyon.  Dec 1992.
    1.13 +*)
    1.14 +
    1.15 +Acc = WF + 
    1.16 +
    1.17 +constdefs
    1.18 +  pred :: "['b, ('a * 'b)set] => 'a set"        (*Set of predecessors*)
    1.19 +  "pred x r == {y. (y,x):r}"
    1.20 +
    1.21 +consts
    1.22 +  acc  :: "('a * 'a)set => 'a set"              (*Accessible part*)
    1.23 +
    1.24 +inductive "acc(r)"
    1.25 +  intrs
    1.26 +    pred    "pred a r: Pow(acc(r)) ==> a: acc(r)"
    1.27 +  monos     "[Pow_mono]"
    1.28 +
    1.29 +end