proposition: Lemma coord_vbasis v U : v \in U -> v = \sum_(i < \dim U) coord (vbasis U) i v *: (vbasis U)`_i.
proof: Proof. exact: coord_basis (vbasisP U). Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)