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| Mirrors > Home > ILE Home > Th. List > nfned | GIF version | ||
| Description: Bound-variable hypothesis builder for inequality. (Contributed by NM, 10-Nov-2007.) (Revised by Mario Carneiro, 7-Oct-2016.) | 
| Ref | Expression | 
|---|---|
| nfned.1 | ⊢ (𝜑 → Ⅎ𝑥𝐴) | 
| nfned.2 | ⊢ (𝜑 → Ⅎ𝑥𝐵) | 
| Ref | Expression | 
|---|---|
| nfned | ⊢ (𝜑 → Ⅎ𝑥 𝐴 ≠ 𝐵) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | df-ne 2368 | . 2 ⊢ (𝐴 ≠ 𝐵 ↔ ¬ 𝐴 = 𝐵) | |
| 2 | nfned.1 | . . . 4 ⊢ (𝜑 → Ⅎ𝑥𝐴) | |
| 3 | nfned.2 | . . . 4 ⊢ (𝜑 → Ⅎ𝑥𝐵) | |
| 4 | 2, 3 | nfeqd 2354 | . . 3 ⊢ (𝜑 → Ⅎ𝑥 𝐴 = 𝐵) | 
| 5 | 4 | nfnd 1671 | . 2 ⊢ (𝜑 → Ⅎ𝑥 ¬ 𝐴 = 𝐵) | 
| 6 | 1, 5 | nfxfrd 1489 | 1 ⊢ (𝜑 → Ⅎ𝑥 𝐴 ≠ 𝐵) | 
| Colors of variables: wff set class | 
| Syntax hints: ¬ wn 3 → wi 4 = wceq 1364 Ⅎwnf 1474 Ⅎwnfc 2326 ≠ 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-5 1461 ax-7 1462 ax-gen 1463 ax-ie2 1508 ax-4 1524 ax-17 1540 ax-ial 1548 ax-i5r 1549 ax-ext 2178 | 
| This theorem depends on definitions: df-bi 117 df-tru 1367 df-fal 1370 df-nf 1475 df-cleq 2189 df-nfc 2328 df-ne 2368 | 
| This theorem is referenced by: (None) | 
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