((P1 -* P2))(H2 ∪ H), P0(H2), P1(H1), H2 ⊥ H1, H ⊥ H2, H ⊥ H1 ⊦ P2((H2 ∪ H1) ∪ H)
Used simplifier rules: ⊦ H0 ⊥ H1 → H1 ⊥ H0; (s)