⊦ (∃ H0. H0 ⊥ H ∧ P0(H0) ∧ P1(H0 ∪ H)) ↔ ¬(∀ H0. H0 ⊥ H ∧ P0(H0) → ¬ P1(H0 ∪ H))
Used simplifier rules: not: ⊦ (¬ P0)(H) ↔ ¬ P0(H);