Definition lset_same_support {A} (lset1 lset2 : AMap.t A) :=
forall loc,
AMap.find loc lset1 = None <->
AMap.find loc lset2 = None.

Lemma lset_same_support_trans {A} (m1 m2 m3 : AMap.t A) :
lset_same_support m1 m2 ->
lset_same_support m2 m3 ->
lset_same_support m1 m3.