| ⊢ | ( f) g ≡ (f g) | NextYields |
Proof:
1 | ⊢ ( f) ; ¬g ≡ (f ; ¬g) | |
2 | ⊢ ¬(( f) ; ¬g) ≡¬ (f ; ¬g) | |
3 | ⊢ ( f) g ≡¬ (f ; ¬g) | 2, def. of |
4 | ⊢ ¬ (f ; ¬g) ≡¬(f ; ¬g) | |
5 | ⊢ ( f) g ≡¬(f ; ¬g) | |
6 | ⊢ ( f) g ≡ (f g) | 5, def. of |
qed