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Mirrors > Home > ILE Home > Th. List > neeq12i | GIF version |
Description: Inference for inequality. (Contributed by NM, 24-Jul-2012.) |
Ref | Expression |
---|---|
neeq1i.1 | ⊢ 𝐴 = 𝐵 |
neeq12i.2 | ⊢ 𝐶 = 𝐷 |
Ref | Expression |
---|---|
neeq12i | ⊢ (𝐴 ≠ 𝐶 ↔ 𝐵 ≠ 𝐷) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | neeq12i.2 | . . 3 ⊢ 𝐶 = 𝐷 | |
2 | 1 | neeq2i 2363 | . 2 ⊢ (𝐴 ≠ 𝐶 ↔ 𝐴 ≠ 𝐷) |
3 | neeq1i.1 | . . 3 ⊢ 𝐴 = 𝐵 | |
4 | 3 | neeq1i 2362 | . 2 ⊢ (𝐴 ≠ 𝐷 ↔ 𝐵 ≠ 𝐷) |
5 | 2, 4 | bitri 184 | 1 ⊢ (𝐴 ≠ 𝐶 ↔ 𝐵 ≠ 𝐷) |
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