proposition: Lemma trace_addc c lc : trace (map (addc c) lc) = trace lc.
proof: Proof. by case: lc => //= c0 lc; rewrite [pairmap _ _ _](ptrace_addc _ (_ :: _)). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype)