fun f(bitstring, bitstring, bitstring): bitstring.

equation forall x: bitstring, y: bitstring, z: bitstring;
	 f(x,y,z) = f(y,x,z).
equation forall x: bitstring, y: bitstring, z: bitstring;
	 f(x,y,z) = f(x,z,y).

free a, b, c: bitstring [private].
free d: channel.

query attacker(f(c,b,a)).

process
	out(d, f(a,b,c))

(* EXPECTPV
RESULT not attacker(f(c[],b[],a[])) is false.
0.008s (user 0.004s + system 0.004s), max rss 7788K
END *)
