simplify; apply (cmpP ? t t1); simplify; intros (Ett1);
[1: cut (count (sub_eqType d p) (cmp (sub_eqType d p) {t,Ht})
(filter d (sigma d p) (if_p d p) l) = O); [1:rewrite > Hcut; reflexivity]
simplify; apply (cmpP ? t t1); simplify; intros (Ett1);
[1: cut (count (sub_eqType d p) (cmp (sub_eqType d p) {t,Ht})
(filter d (sigma d p) (if_p d p) l) = O); [1:rewrite > Hcut; reflexivity]