fact: Definition rcs_poly (R : idomainType) (p : {poly R}) n := ('X * p) %% ('X^n - 1).
imports: mathcomp(all_ssreflect ssralg poly polydiv fingroup perm) mathcomp(finalg zmodp matrix mxalgebra mxpoly polydiv vector) ssralg_ext poly_ext f2 hamming linearcode dft