proposition: Lemma size_lagrange_ i : size (lagrange_ i) = n.
proof: Proof. by rewrite lagrangeE size_lagrange_def. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice fintype tuple) mathcomp(bigop binomial finset finfun ssralg countalg finalg poly polydiv) mathcomp(perm fingroup matrix mxalgebra mxpoly vector countalg)