free c: channel.
free m,n: bitstring.

set swapping = "@_23_@_20 -> @_22_@_21".

let P = sync 1;
        out(c,choice[m,n]).

let Q = sync 1;
        out(c,choice[n,m]).

process
    (
        out(c,m);
	P
    )| Q

(* EXPECTPV
RESULT Observational equivalence is true.
0.016s (user 0.012s + system 0.004s), max rss 8716K
END *)
