H0 ⊥ H1, r ∈ H0 ∨ r ∈ H1 ⊦ (H0 ∪ H1)[r] = (r ∈ H0 ⊃ H0[r];H1[r])
Used simplifier rules: in-uni: ⊦ H0 ⊥ H1 → (r ∈ H0 ∪ H1 ↔ r ∈ H0 ∨ r ∈ H1);