Ltac normalize := repeat (auto with norm; normalize1).Definition mark {A: Type} (i: nat) (j: A) := j.

Lemma swap_mark1 {A} {NA: NatDed A}{SA: SepLog A}: forall i j (Pi Pj B : A), (i<j)%nat -> B * mark i Pi * mark j Pj = B * mark j Pj * mark i Pi.