Proof of Theorem ifpbi123
Step | Hyp | Ref
| Expression |
1 | | simp1 1054 |
. . . 4
⊢ (((𝜑 ↔ 𝜓) ∧ (𝜒 ↔ 𝜃) ∧ (𝜏 ↔ 𝜂)) → (𝜑 ↔ 𝜓)) |
2 | | simp2 1055 |
. . . 4
⊢ (((𝜑 ↔ 𝜓) ∧ (𝜒 ↔ 𝜃) ∧ (𝜏 ↔ 𝜂)) → (𝜒 ↔ 𝜃)) |
3 | 1, 2 | imbi12d 333 |
. . 3
⊢ (((𝜑 ↔ 𝜓) ∧ (𝜒 ↔ 𝜃) ∧ (𝜏 ↔ 𝜂)) → ((𝜑 → 𝜒) ↔ (𝜓 → 𝜃))) |
4 | 1 | notbid 307 |
. . . 4
⊢ (((𝜑 ↔ 𝜓) ∧ (𝜒 ↔ 𝜃) ∧ (𝜏 ↔ 𝜂)) → (¬ 𝜑 ↔ ¬ 𝜓)) |
5 | | simp3 1056 |
. . . 4
⊢ (((𝜑 ↔ 𝜓) ∧ (𝜒 ↔ 𝜃) ∧ (𝜏 ↔ 𝜂)) → (𝜏 ↔ 𝜂)) |
6 | 4, 5 | imbi12d 333 |
. . 3
⊢ (((𝜑 ↔ 𝜓) ∧ (𝜒 ↔ 𝜃) ∧ (𝜏 ↔ 𝜂)) → ((¬ 𝜑 → 𝜏) ↔ (¬ 𝜓 → 𝜂))) |
7 | 3, 6 | anbi12d 743 |
. 2
⊢ (((𝜑 ↔ 𝜓) ∧ (𝜒 ↔ 𝜃) ∧ (𝜏 ↔ 𝜂)) → (((𝜑 → 𝜒) ∧ (¬ 𝜑 → 𝜏)) ↔ ((𝜓 → 𝜃) ∧ (¬ 𝜓 → 𝜂)))) |
8 | | dfifp2 1008 |
. 2
⊢
(if-(𝜑, 𝜒, 𝜏) ↔ ((𝜑 → 𝜒) ∧ (¬ 𝜑 → 𝜏))) |
9 | | dfifp2 1008 |
. 2
⊢
(if-(𝜓, 𝜃, 𝜂) ↔ ((𝜓 → 𝜃) ∧ (¬ 𝜓 → 𝜂))) |
10 | 7, 8, 9 | 3bitr4g 302 |
1
⊢ (((𝜑 ↔ 𝜓) ∧ (𝜒 ↔ 𝜃) ∧ (𝜏 ↔ 𝜂)) → (if-(𝜑, 𝜒, 𝜏) ↔ if-(𝜓, 𝜃, 𝜂))) |