proposition: Lemma exp0rz n : 0 ^ n = (n == 0)%:~R :> R.
proof: Proof. by case: (intP n)=> // m; rewrite -?exprz_inv ?invr0 exprSz mul0r. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)