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| Mirrors > Home > ILE Home > Th. List > necon1abiddc | GIF version | ||
| Description: Contrapositive deduction for inequality. (Contributed by Jim Kingdon, 16-May-2018.) |
| Ref | Expression |
|---|---|
| necon1abiddc.1 | ⊢ (𝜑 → (DECID 𝜓 → (¬ 𝜓 ↔ 𝐴 = 𝐵))) |
| Ref | Expression |
|---|---|
| necon1abiddc | ⊢ (𝜑 → (DECID 𝜓 → (𝐴 ≠ 𝐵 ↔ 𝜓))) |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | necon1abiddc.1 | . . 3 ⊢ (𝜑 → (DECID 𝜓 → (¬ 𝜓 ↔ 𝐴 = 𝐵))) | |
| 2 | 1 | con1biddc 877 | . 2 ⊢ (𝜑 → (DECID 𝜓 → (¬ 𝐴 = 𝐵 ↔ 𝜓))) |
| 3 | df-ne 2368 | . . 3 ⊢ (𝐴 ≠ 𝐵 ↔ ¬ 𝐴 = 𝐵) | |
| 4 | 3 | bibi1i 228 | . 2 ⊢ ((𝐴 ≠ 𝐵 ↔ 𝜓) ↔ (¬ 𝐴 = 𝐵 ↔ 𝜓)) |
| 5 | 2, 4 | imbitrrdi 162 | 1 ⊢ (𝜑 → (DECID 𝜓 → (𝐴 ≠ 𝐵 ↔ 𝜓))) |
| Colors of variables: wff set class |
| Syntax hints: ¬ wn 3 → wi 4 ↔ wb 105 DECID wdc 835 = wceq 1364 ≠ wne 2367 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 615 ax-in2 616 ax-io 710 |
| This theorem depends on definitions: df-bi 117 df-stab 832 df-dc 836 df-ne 2368 |
| This theorem is referenced by: necon2abiddc 2433 |
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