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Mirrors > Home > MPE Home > Th. List > necon1bbii | Structured version Visualization version GIF version |
Description: Contrapositive inference for inequality. (Contributed by NM, 17-Mar-2007.) (Proof shortened by Wolf Lammen, 24-Nov-2019.) |
Ref | Expression |
---|---|
necon1bbii.1 | ⊢ (𝐴 ≠ 𝐵 ↔ 𝜑) |
Ref | Expression |
---|---|
necon1bbii | ⊢ (¬ 𝜑 ↔ 𝐴 = 𝐵) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nne 3020 | . 2 ⊢ (¬ 𝐴 ≠ 𝐵 ↔ 𝐴 = 𝐵) | |
2 | necon1bbii.1 | . 2 ⊢ (𝐴 ≠ 𝐵 ↔ 𝜑) | |
3 | 1, 2 | xchnxbi 333 | 1 ⊢ (¬ 𝜑 ↔ 𝐴 = 𝐵) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 ↔ wb 207 = wceq 1528 ≠ wne 3016 |
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 208 df-ne 3017 |
This theorem is referenced by: necon2bbii 3067 intnex 5233 class2set 5246 csbopab 5434 relimasn 5946 modom 8708 supval2 8908 fzo0 13051 vma1 25671 lgsquadlem3 25886 ordtconnlem1 31067 |
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