Description: Theorem to move a conjunct in and out of a negation. (Contributed by NM, 9-Nov-2003)
| Ref | Expression | ||
|---|---|---|---|
| Assertion | nan | ⊢ ( ( 𝜑 → ¬ ( 𝜓 ∧ 𝜒 ) ) ↔ ( ( 𝜑 ∧ 𝜓 ) → ¬ 𝜒 ) ) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | impexp | ⊢ ( ( ( 𝜑 ∧ 𝜓 ) → ¬ 𝜒 ) ↔ ( 𝜑 → ( 𝜓 → ¬ 𝜒 ) ) ) | |
| 2 | imnan | ⊢ ( ( 𝜓 → ¬ 𝜒 ) ↔ ¬ ( 𝜓 ∧ 𝜒 ) ) | |
| 3 | 2 | imbi2i | ⊢ ( ( 𝜑 → ( 𝜓 → ¬ 𝜒 ) ) ↔ ( 𝜑 → ¬ ( 𝜓 ∧ 𝜒 ) ) ) | 
| 4 | 1 3 | bitr2i | ⊢ ( ( 𝜑 → ¬ ( 𝜓 ∧ 𝜒 ) ) ↔ ( ( 𝜑 ∧ 𝜓 ) → ¬ 𝜒 ) ) |