r ∈ H1 ∪ H0, H0 ⊥ H1, r ∈ H1 ∨ r ∈ H0 ⊦ (r ∈ H1 ⊃ H1[r];H0[r]) = (H0 ∪ H1)[r]
Used simplifier rules: disj-com-rw: ⊦ H0 ⊥ H1 → H1 ⊥ H0;