proposition: Fact size_bal_of_Dyck rt w : size (take (size w) (rotr rt (rcons w }}))) == n.*2.
proof: Proof. by rewrite size_take size_rot size_rcons ltnS leqnn size_tuple. Qed.
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(div ssralg ssrint ssrnum binomial) tools combclass bintree