Hint Rewrite @sublist_nil' using list_solve: sublist.
Hint Rewrite @app_nil_l : sublist.
Hint Rewrite @Zlength_rev : sublist.
Hint Rewrite @sublist_rejoin' using list_solve : sublist.

Lemma upd_Znth_lookup K {A}{d: Inhabitant A}: forall l (L:Zlength l = K) i j (v:A) (I: 0<=i<K) (J: 0<=j<K),
(i=j /\ Znth i (upd_Znth j l v) = v) \/
(i<>j /\ Znth i (upd_Znth j l v) = Znth i l).