proposition: Lemma directvEgeq (S : addv_expr) : directv (unwrap S) = (\dim (unwrap S) >= unwrap (addv_dim S)).
proof: Proof. by rewrite leq_eqVlt ltnNge eq_sym !dimv_sum_leqif orbF. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)