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Mirrors > Home > MPE Home > Th. List > ifpnOLD | Structured version Visualization version GIF version |
Description: Obsolete version of ifpn 1070 as of 5-May-2024. (Contributed by BJ, 30-Sep-2019.) (Proof modification is discouraged.) (New usage is discouraged.) |
Ref | Expression |
---|---|
ifpnOLD | ⊢ (if-(𝜑, 𝜓, 𝜒) ↔ if-(¬ 𝜑, 𝜒, 𝜓)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | notnotb 319 | . . . 4 ⊢ (𝜑 ↔ ¬ ¬ 𝜑) | |
2 | 1 | imbi1i 354 | . . 3 ⊢ ((𝜑 → 𝜓) ↔ (¬ ¬ 𝜑 → 𝜓)) |
3 | 2 | anbi2ci 628 | . 2 ⊢ (((𝜑 → 𝜓) ∧ (¬ 𝜑 → 𝜒)) ↔ ((¬ 𝜑 → 𝜒) ∧ (¬ ¬ 𝜑 → 𝜓))) |
4 | dfifp2 1061 | . 2 ⊢ (if-(𝜑, 𝜓, 𝜒) ↔ ((𝜑 → 𝜓) ∧ (¬ 𝜑 → 𝜒))) | |
5 | dfifp2 1061 | . 2 ⊢ (if-(¬ 𝜑, 𝜒, 𝜓) ↔ ((¬ 𝜑 → 𝜒) ∧ (¬ ¬ 𝜑 → 𝜓))) | |
6 | 3, 4, 5 | 3bitr4i 307 | 1 ⊢ (if-(𝜑, 𝜓, 𝜒) ↔ if-(¬ 𝜑, 𝜒, 𝜓)) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 209 ∧ wa 400 if-wif 1059 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 |
This theorem depends on definitions: df-bi 210 df-an 401 df-or 846 df-ifp 1060 |
This theorem is referenced by: (None) |
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