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