⊦ H0 ⊥ H1 ↔ (∀ r. ¬ r ∈ H0 ∨ ¬ r ∈ H1)
⊦ (∀ r0. ¬ r0 ∈ H0 ∨ ¬ r0 ∈ (H1 ++ r)[r, o]) ↔ H0 ⊥ H1 ∧ ¬ r ∈ H0, r = null, r ∈ H1
Used terms: (H1 ++ r)[r, o], H0