fact: Definition constt x pi := x ^+ (chinese #[x]`_pi #[x]`_pi^' 1 0).
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq div) mathcomp(fintype bigop finset prime fingroup morphism) mathcomp(gfunctor automorphism quotient action gproduct) mathcomp(cyclic)