free c:channel.
free a:bitstring.

fun enc(bitstring,bitstring):bitstring.
reduc forall x:bitstring,y:bitstring; dec(enc(x,y),y) = x.

equivalence
  phase 1;
  out(c,a)

  phase 2;
  out(c,a)

(* EXPECTPV
RESULT no biprocess can be computed
0.004s (user 0.004s + system 0.000s), max rss 6584K
END *)
