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Mirrors > Home > MPE Home > Th. List > necon1abid | Structured version Visualization version GIF version |
Description: Contrapositive deduction for inequality. (Contributed by NM, 21-Aug-2007.) (Proof shortened by Wolf Lammen, 24-Nov-2019.) |
Ref | Expression |
---|---|
necon1abid.1 | ⊢ (𝜑 → (¬ 𝜓 ↔ 𝐴 = 𝐵)) |
Ref | Expression |
---|---|
necon1abid | ⊢ (𝜑 → (𝐴 ≠ 𝐵 ↔ 𝜓)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | notnotb 314 | . 2 ⊢ (𝜓 ↔ ¬ ¬ 𝜓) | |
2 | necon1abid.1 | . . 3 ⊢ (𝜑 → (¬ 𝜓 ↔ 𝐴 = 𝐵)) | |
3 | 2 | necon3bbid 2982 | . 2 ⊢ (𝜑 → (¬ ¬ 𝜓 ↔ 𝐴 ≠ 𝐵)) |
4 | 1, 3 | bitr2id 283 | 1 ⊢ (𝜑 → (𝐴 ≠ 𝐵 ↔ 𝜓)) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 205 = wceq 1541 ≠ wne 2944 |
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 206 df-ne 2945 |
This theorem is referenced by: lttri2 11041 xrlttri2 12858 ioon0 13087 lssne0 20193 xmetgt0 23492 sotrine 33713 |
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