Give terms denoting proofs of
- (A -> B -> C) -> (B -> A -> C)
- (Πa:A.Πb:B.C(a,b)) -> (Πb:B.Πa:A.C(a,b))
- (A -> B) -> (B -> C) -> (A -> C)
- A ∧ (B ∧ C) -> B ∧ (A ∧ C)
- (A ∧ B) ∧ C -> (B ∧ A) ∧ C
- A ∧ (B ∧ C) -> (A ∧ B) ∧ C
- Σa:A.Σb:B.C(a,b) -> Σb:B.Σa:A.C(a,b)
- Σc:A×B.C(c) -> Σc:B×A.C(⟨c.2,c.1⟩)
- Σb:A.Σa:B.C(a,b) -> Σc:A×B.C(c.1,c.2)