Proof of Theorem imoverbi-P4.30b
| Step | Hyp | Ref
| Expression |
| 1 | | imoverbi-P4.30-L2 478 |
. 2
⊢ ((𝜑 → (𝜓 ↔
𝜒)) ↔ ((𝜑
→ (𝜓 → 𝜒)) ∧ (𝜑 →
(𝜒 → 𝜓)))) |
| 2 | | imoverim-P4.30a 477 |
. . 3
⊢ ((𝜑 → (𝜓 →
𝜒)) ↔ ((𝜑
→ 𝜓) → (𝜑 → 𝜒))) |
| 3 | | imoverim-P4.30a 477 |
. . 3
⊢ ((𝜑 → (𝜒 →
𝜓)) ↔ ((𝜑
→ 𝜒) → (𝜑 → 𝜓))) |
| 4 | 2, 3 | subandd-P3.42c.RC 344 |
. 2
⊢ (((𝜑 → (𝜓 →
𝜒)) ∧ (𝜑
→ (𝜒 → 𝜓))) ↔ (((𝜑 →
𝜓) → (𝜑
→ 𝜒)) ∧ ((𝜑 → 𝜒) →
(𝜑 → 𝜓)))) |
| 5 | | dfbi-P3.47 358 |
. . 3
⊢ (((𝜑 → 𝜓) ↔
(𝜑 → 𝜒))
↔ (((𝜑 → 𝜓) → (𝜑 →
𝜒)) ∧ ((𝜑
→ 𝜒) → (𝜑 → 𝜓)))) |
| 6 | 5 | bisym-P3.33b.RC 299 |
. 2
⊢ ((((𝜑 → 𝜓) →
(𝜑 → 𝜒))
∧ ((𝜑 → 𝜒) → (𝜑 →
𝜓))) ↔ ((𝜑
→ 𝜓) ↔ (𝜑 → 𝜒))) |
| 7 | 1, 4, 6 | dbitrns-P4.16.RC 429 |
1
⊢ ((𝜑 → (𝜓 ↔
𝜒)) ↔ ((𝜑
→ 𝜓) ↔ (𝜑 → 𝜒))) |