fact: Definition famY mz : {ffun 'I_m -> 'X_{1.. n < d.+1}} := [ffun i : 'I_m => BMultinom (famY_subproof mz i)].
imports: HB(structures) mathcomp(all_ssreflect) mathcomp(ssrint rat ssralg ssrnum algC matrix vector) mathcomp(mpoly) tools partition ordtype antisym Schur_mpoly Schur_altdef sympoly homogsym permcent