proposition: Lemma addv_pi1_proj U V w (pi1 := addv_pi1 U V) : pi1 (pi1 w) = pi1 w.
proof: Proof. by rewrite daddv_pi_proj // capv_diff. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop finfun tuple) mathcomp(ssralg matrix mxalgebra zmodp)