fact: Definition col_perm (s : 'S_n) A := \matrix[col_perm_key]_(i, j) A i (s j).
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq choice) mathcomp(fintype finfun bigop finset fingroup perm order) mathcomp(div prime binomial ssralg countalg finalg zmodp)