proposition: Lemma memc0_ctrace et : (Color0 \in ctrace et) = (sumt et == Color0) || (Color0 \in et).
proof: Proof. by rewrite mem_rcons eq_sym. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype)