fact: Definition exprz (R : unitRingType) (x : R) (n : int) := match n with | Posz n => x ^+ n | Negz n => x ^- (n.+1) end.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)