Section SepAlgCompat.
Context A `{SA: SepAlg A}.
Definition compat (a b : A) := exists s, sa_mul a b s.
Definition subheap (a b : A) := exists c, sa_mul a c b.

Lemma sa_mul_monR (a b c d : A) (Habc : sa_mul a b c) (Hcd: rel c d) : sa_mul a b d.