| H ⊥ H0, H1 ⊥ H, H0 ⊥ H1 ⊦ (H0 ∪ H1) ∪ H = H0 ∪ H1 ∪ H |
⊦ H0 = H1 ↔ (∀ r. (r ∈ H0 ↔ r ∈ H1) ∧ (r ∈ H0 → H0[r] = H1[r]))
H0 ⊥ H1, H1 ⊥ H, H ⊥ H0 ⊦ ∀ r. (r ∈ (H0 ∪ H1) ∪ H ↔ r ∈ H0 ∪ H1 ∪ H) ∧ (r ∈ (H0 ∪ H1) ∪ H → ((H0 ∪ H1) ∪ H)[r] = (H0 ∪ H1 ∪ H)[r])
Used terms: H0 ∪ H1 ∪ H, (H0 ∪ H1) ∪ H