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Mirrors > Home > MPE Home > Th. List > Mathboxes > compne | Structured version Visualization version GIF version |
Description: The complement of 𝐴 is not equal to 𝐴. (Contributed by Andrew Salmon, 15-Jul-2011.) (Proof shortened by BJ, 11-Nov-2021.) |
Ref | Expression |
---|---|
compne | ⊢ (V ∖ 𝐴) ≠ 𝐴 |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | vn0 4338 | . 2 ⊢ V ≠ ∅ | |
2 | id 22 | . . . . . . 7 ⊢ ((V ∖ 𝐴) = 𝐴 → (V ∖ 𝐴) = 𝐴) | |
3 | difeq1 4115 | . . . . . . . 8 ⊢ ((V ∖ 𝐴) = 𝐴 → ((V ∖ 𝐴) ∖ 𝐴) = (𝐴 ∖ 𝐴)) | |
4 | difabs 4293 | . . . . . . . 8 ⊢ ((V ∖ 𝐴) ∖ 𝐴) = (V ∖ 𝐴) | |
5 | difid 4370 | . . . . . . . 8 ⊢ (𝐴 ∖ 𝐴) = ∅ | |
6 | 3, 4, 5 | 3eqtr3g 2795 | . . . . . . 7 ⊢ ((V ∖ 𝐴) = 𝐴 → (V ∖ 𝐴) = ∅) |
7 | 2, 6 | eqtr3d 2774 | . . . . . 6 ⊢ ((V ∖ 𝐴) = 𝐴 → 𝐴 = ∅) |
8 | 7 | difeq2d 4122 | . . . . 5 ⊢ ((V ∖ 𝐴) = 𝐴 → (V ∖ 𝐴) = (V ∖ ∅)) |
9 | dif0 4372 | . . . . 5 ⊢ (V ∖ ∅) = V | |
10 | 8, 9 | eqtrdi 2788 | . . . 4 ⊢ ((V ∖ 𝐴) = 𝐴 → (V ∖ 𝐴) = V) |
11 | 10, 6 | eqtr3d 2774 | . . 3 ⊢ ((V ∖ 𝐴) = 𝐴 → V = ∅) |
12 | 11 | necon3i 2973 | . 2 ⊢ (V ≠ ∅ → (V ∖ 𝐴) ≠ 𝐴) |
13 | 1, 12 | ax-mp 5 | 1 ⊢ (V ∖ 𝐴) ≠ 𝐴 |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1541 ≠ wne 2940 Vcvv 3474 ∖ cdif 3945 ∅c0 4322 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1797 ax-4 1811 ax-5 1913 ax-6 1971 ax-7 2011 ax-8 2108 ax-9 2116 ax-ext 2703 |
This theorem depends on definitions: df-bi 206 df-an 397 df-or 846 df-tru 1544 df-fal 1554 df-ex 1782 df-sb 2068 df-clab 2710 df-cleq 2724 df-clel 2810 df-ne 2941 df-rab 3433 df-v 3476 df-dif 3951 df-un 3953 df-in 3955 df-nul 4323 |
This theorem is referenced by: (None) |
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