fact: Parameter set_nth_correct : forall pi p n ai a, pi >:: p -> ai >: a -> set_nth pi n ai >:: PolR.set_nth p n a.
imports: Coq(ZArith Reals) Coquelicot(Coquelicot) mathcomp.ssreflect(ssreflect ssrfun ssrbool eqtype ssrnat seq fintype bigop) Flocq(Core) Stdlib MathComp Interval Xreal Basic_rec