src/HOLCF/dnat2.thy

Bad version of Otway-Rees and the new attack on it

(*  Title: 	HOLCF/dnat2.thy
    ID:         $Id$
    Author: 	Franz Regensburger
    Copyright   1993 Technische Universitaet Muenchen

Additional constants for dnat

*)

Dnat2 = Dnat +

consts

iterator	:: "dnat -> ('a -> 'a) -> 'a -> 'a"


rules

iterator_def	"iterator = fix[LAM h n f x.\
\	dnat_when[x][LAM m.f[h[m][f][x]]][n]]"


end


(*

		iterator[UU][f][x] = UU
		iterator[dzero][f][x] = x
      n~=UU --> iterator[dsucc[n]][f][x] = f[iterator[n][f][x]]
*)