Section AlwaysInject.
Variables (V W : world) (K : hooks) (A : Type) (w : injects V W K) (this: nid).
Notation W2 := (inj_ext w).

Lemma rely_ext i j s :
i \In Coh V ->
network_rely W this (i \+ j) s ->
exists i' j', s = i' \+ j' /\ i' \In Coh V.