| ⊢ (f ≡ g) ≡ (f ⊃ g) ∧ (g ⊃ f) | BfEqvSplit | 
Proof:
| 1 | (f ≡ g) ≡ (f  ⊃ g) ∧ (g  ⊃ f)                      | |
| 2  |  (f ≡ g) ≡ ((f  ⊃ g) ∧ (g  ⊃ f))                  | |
| 3  |  ((f  ⊃ g) ∧ (g  ⊃ f)) ≡ (f  ⊃ g) ∧ (g  ⊃ f) | |
| 4  |  (f ≡ g) ≡ (f  ⊃ g) ∧ (g  ⊃ f)                    | 
qed