H0 ∪ H2 = H1 ∪ H3, ((P0 * P1 * true))(H1 ∪ H3), P0(H0), P1(H1), precise(P0), precise(P1), H1 ⊥ H3, H0 ⊥ H2 ⊦ H0 ⊥ H1