Local Hint Resolve lt_x'_x'max le_x'_x'max : a.

Lemma h'_i_eq_mod : M = 1 \/ _Z h'_i = (x' / 2 ^ p) mod 2 ^ w.
elim t_M; intro Ht. right. unfold h'_i. simpl. fold t. rewrite <- Zmod_plus_distr_l. unfold s''_i. unfold x'. unfold r'a.