⊦ ((P0 -* P1))(H) ↔ (∀ H1. H1 ⊥ H ∧ P0(H1) → P1(H1 ∪ H))
⊦ (∃ H0. H0 ⊥ H ∧ P0(H0) ∧ P1(H0 ∪ H)) ↔ ¬(∀ H1. H1 ⊥ H ∧ P0(H1) → (¬ P1)(H1 ∪ H))
Used terms: H, ¬ P1, P0