| ⊢ | f∗∧more ⊃ f∗ ; f | CSAndMoreImpCSChop | 
Proof:
| 1  | ⊢ f∗∧more ≡ (f ∧more) ; f∗                    | |
| 2  | ⊢ empty ∨more                                                                    | |
| 3  | ⊢ f∗⊃empty ∨ (f∗∧more)                                        | |
| 4  | ⊢ (f ∧more) ; f∗⊃ (f ∧more) ∨ ((f ∧more) ; (f∗∧more)) | |
| 5  | ⊢ f∗∧more ∧¬f ⊃ (f ∧more) ; (f∗∧more)                   | |
| 6  | ⊢ f∗≡empty ∨ (f ∧more) ; f∗                   | |
| 7  | ⊢ f∗ ; f ≡ f ∨ ((f ∧more) ; f∗) ; f                          | |
| 8  | ⊢ ((f ∧more) ; f∗) ; f ≡ (f ∧more) ; (f∗ ; f)                   | |
| 9  | ⊢ (f∗∧more) ∧¬(f∗ ; f) ⊃                 | |
| (f ∧more) ; (f∗∧more) ∧¬((f ∧more) ; (f∗ ; f))               | ||
| 10 | ⊢ f ∧more ⊃more                                                               | |
| 11 | ⊢ f∗∧more ⊃ f∗ ; f                                          | 
qed
The following lemma is used in the proof of CSAndMoreImpCSChop: