⊦ H0 = H1 ↔ (∀ r. (r ∈ H0 ↔ r ∈ H1) ∧ (r ∈ H0 → H0[r] = H1[r]))
⊦ r ∈ H, ∀ r0. (r0 ∈ H -- r ↔ r0 ∈ H) ∧ (r0 ∈ H -- r → (H -- r)[r0] = H[r0])
Used terms: H, H -- r