fact: Definition BRprod x y:= Yo (x = \0r) \0r (Yo (inc x BRps) (Yo (y = \0r) \0r (Yo (inc y BRps) (BRprod_aux x y) (BRopp (BRprod_aux x (BRopp y))))) (Yo (y = \0r) \0r (Yo (inc y BRps) (BRopp (BRprod_aux (BRopp x) y)) (BRprod_aux (BRopp x) (BRopp y))))).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)