| ⊢ | f+ ≡ f ∨ (f ; f+) | ChopPlusEqvOrChopChopPlus | 
Proof for  ⊃ :
| 1 | ⊢ f+ ≡ f ∨ (f ∧more) ; f+ | |
| 2  | ⊢ (f ∧more) ; f+ ⊃ f ; f+   | |
| 3  | ⊢ f+ ⊃ f ∨ f ; f+              | 
qed
Proof for ⊂:
| 1 | ⊢ f ⊃ f+                                    | |
| 2  | ⊢ empty ∨more                             | |
| 3  | ⊢ f ⊃empty ∨ (f ∧more)           | |
| 4  | ⊢ f ; f+ ⊃ f+ ∨ (f ∧more) ; f+ | |
| 5  | ⊢ f+ ≡ f ∨ (f ∧more) ; f+        | |
| 6  | ⊢ (f ∧more) ; f+ ⊃ f+               | |
| 7  | ⊢ f ∨ (f ; f+) ⊃ f+                   | 
qed