src/ZF/Trancl.thy

intro_tacsf: replaced ORELSE by APPEND in order to stop
errors that arise when unconstrained equalities appear in the premises. Could
cause runtimes to increase...

(*  Title:      ZF/trancl.thy
    ID:         $Id$
    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
    Copyright   1992  University of Cambridge

Transitive closure of a relation
*)

Trancl = Fixedpt + Perm + "mono" + Rel + 
consts
    rtrancl :: i=>i  ("(_^*)" [100] 100)  (*refl/transitive closure*)
    trancl  :: i=>i  ("(_^+)" [100] 100)  (*transitive closure*)

defs
    rtrancl_def "r^* == lfp(field(r)*field(r), %s. id(field(r)) Un (r O s))"
    trancl_def  "r^+ == r O r^*"
end