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