fact: Definition Exists_row_form k (f : form) := foldr GRing.Exists f (codom (fun i : 'I_d => k * d + i)%N).
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(div fintype tuple finfun bigop fingroup perm) mathcomp(ssralg zmodp matrix mxalgebra poly polydiv)