Proof sep_drop.
Definition sep_pick1 := sep_proj1.

(* Specifications: *)
Lemma sep_pick2:
forall P Q R m, m |= P ** Q ** R -> m |= Q.
Lemma sep_pick3:
forall P Q R S m, m |= P ** Q ** R ** S -> m |= R.
Lemma sep_pick4:
forall P Q R S T m, m |= P ** Q ** R ** S ** T -> m |= S.
Lemma sep_pick5:
forall P Q R S T U m, m |= P ** Q ** R ** S ** T ** U -> m |= T.
Lemma sep_preserved:
forall m m' P Q,
m |= P ** Q ->
(m |= P -> m' |= P) ->
(m |= Q -> m' |= Q) ->
m' |= P ** Q.