Axiom Schemata for F Axiom Schema 1 A ∨ A ⊃ A Axiom Schema 2 A ⊃ (B ∨ A) Axiom Schema 3 A ⊃ B ⊃ (C ∨ A ⊃ (B ∨ C)) Axiom Schema 4 ∀xA ⊃ Sxt A where t is a term free for the individual variable x in A Axiom Schema 5 ∀x(A ∨ B) ⊃ (A ∨ ∀xB) provided that x is not free in A