| ⊢ | f ∧ (g ; g1) ⊃ (f ∧ g) ; (f ∧ g1) | BaAndChopImport | 
Proof:
| 1 | ⊢  f ⊃ f                                 | |
| 2  | ⊢  f ∧ (g ; g1) ⊃ (f ∧ g) ; g1                 | |
| 3  | ⊢  f ⊃ f                                 | |
| 4  | ⊢  f ∧ (f ∧ g) ; g1 ⊃ (f ∧ g) ; (f ∧ g1) | |
| 5  | ⊢  f ∧ (g ; g1) ⊃ (f ∧ g) ; (f ∧ g1)       | 
qed