proposition: Lemma exp2R_add s1 s2 : exp2R (s1 + s2) == exp2R s1 * exp2R s2.
proof: Proof. by rewrite /exp2R expnD -intRM. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype tuple path fingraph bigop order ssralg) mathcomp(ssrnum ssrint div intdiv) fourcolor(hypermap geometry coloring grid matte) fourcolor(real realplane) Coq(Setoid Morphisms) fourcolor(realsyntax realprop)