Section StrongRelaxedInjections.
Admitted.

Lemma inject_mem_effect_strong_compose:
forall (j12 j23 : meminj) (x1 x2 x3 : mem_effect),
inject_mem_effect_strong j12 x1 x2 ->
inject_mem_effect j23 x2 x3 -> inject_mem_effect (compose_meminj j12 j23) x1 x3.