Description: The import-export theorem ( impexp ) for biconditionals (deduction form). (Contributed by Zhi Wang, 3-Sep-2024)
| Ref | Expression | ||
|---|---|---|---|
| Hypothesis | exp12bd.1 | ⊢ ( 𝜑 → ( ( ( 𝜓 ∧ 𝜒 ) → 𝜃 ) ↔ ( ( 𝜏 ∧ 𝜂 ) → 𝜁 ) ) ) | |
| Assertion | exp12bd | ⊢ ( 𝜑 → ( ( 𝜓 → ( 𝜒 → 𝜃 ) ) ↔ ( 𝜏 → ( 𝜂 → 𝜁 ) ) ) ) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | exp12bd.1 | ⊢ ( 𝜑 → ( ( ( 𝜓 ∧ 𝜒 ) → 𝜃 ) ↔ ( ( 𝜏 ∧ 𝜂 ) → 𝜁 ) ) ) | |
| 2 | impexp | ⊢ ( ( ( 𝜓 ∧ 𝜒 ) → 𝜃 ) ↔ ( 𝜓 → ( 𝜒 → 𝜃 ) ) ) | |
| 3 | impexp | ⊢ ( ( ( 𝜏 ∧ 𝜂 ) → 𝜁 ) ↔ ( 𝜏 → ( 𝜂 → 𝜁 ) ) ) | |
| 4 | 1 2 3 | 3bitr3g | ⊢ ( 𝜑 → ( ( 𝜓 → ( 𝜒 → 𝜃 ) ) ↔ ( 𝜏 → ( 𝜂 → 𝜁 ) ) ) ) |