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| Mirrors > Home > MPE Home > Th. List > Mathboxes > vsn | Structured version Visualization version GIF version | ||
| Description: The singleton of the universal class is the empty set. (Contributed by Zhi Wang, 19-Sep-2024.) |
| Ref | Expression |
|---|---|
| vsn | ⊢ {V} = ∅ |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | vprc 5270 | . 2 ⊢ ¬ V ∈ V | |
| 2 | snprc 4676 | . 2 ⊢ (¬ V ∈ V ↔ {V} = ∅) | |
| 3 | 1, 2 | mpbi 232 | 1 ⊢ {V} = ∅ |
| Colors of variables: wff setvar class |
| Syntax hints: ¬ wn 3 = wceq 1560 ∈ wcel 2142 Vcvv 3454 ∅c0 4285 {csn 4582 |
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1815 ax-4 1829 ax-5 1930 ax-6 1987 ax-7 2028 ax-8 2144 ax-9 2152 ax-ext 2734 ax-sep 5246 |
| This theorem depends on definitions: df-bi 209 df-an 400 df-tru 1563 df-fal 1573 df-ex 1800 df-sb 2091 df-clab 2741 df-cleq 2754 df-clel 2837 df-v 3456 df-dif 3907 df-nul 4286 df-sn 4583 |
| This theorem is referenced by: mo0 49435 setc1oterm 50112 |
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