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Mirrors > Home > MPE Home > Th. List > Mathboxes > eu0 | Structured version Visualization version GIF version |
Description: There is only one empty set. (Contributed by RP, 1-Oct-2023.) |
Ref | Expression |
---|---|
eu0 | ⊢ (∀𝑥 ¬ 𝑥 ∈ ∅ ∧ ∃!𝑥∀𝑦 ¬ 𝑦 ∈ 𝑥) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | noel 4231 | . . 3 ⊢ ¬ 𝑥 ∈ ∅ | |
2 | 1 | ax-gen 1803 | . 2 ⊢ ∀𝑥 ¬ 𝑥 ∈ ∅ |
3 | ax-nul 5184 | . . 3 ⊢ ∃𝑥∀𝑦 ¬ 𝑦 ∈ 𝑥 | |
4 | nulmo 2713 | . . 3 ⊢ ∃*𝑥∀𝑦 ¬ 𝑦 ∈ 𝑥 | |
5 | df-eu 2568 | . . 3 ⊢ (∃!𝑥∀𝑦 ¬ 𝑦 ∈ 𝑥 ↔ (∃𝑥∀𝑦 ¬ 𝑦 ∈ 𝑥 ∧ ∃*𝑥∀𝑦 ¬ 𝑦 ∈ 𝑥)) | |
6 | 3, 4, 5 | mpbir2an 711 | . 2 ⊢ ∃!𝑥∀𝑦 ¬ 𝑦 ∈ 𝑥 |
7 | 2, 6 | pm3.2i 474 | 1 ⊢ (∀𝑥 ¬ 𝑥 ∈ ∅ ∧ ∃!𝑥∀𝑦 ¬ 𝑦 ∈ 𝑥) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 ∧ wa 399 ∀wal 1541 ∃wex 1787 ∈ wcel 2112 ∃*wmo 2537 ∃!weu 2567 ∅c0 4223 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1803 ax-4 1817 ax-5 1918 ax-6 1976 ax-7 2018 ax-8 2114 ax-9 2122 ax-10 2143 ax-11 2160 ax-12 2177 ax-ext 2708 ax-nul 5184 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 848 df-tru 1546 df-fal 1556 df-ex 1788 df-nf 1792 df-sb 2073 df-mo 2539 df-eu 2568 df-clab 2715 df-cleq 2728 df-clel 2809 df-dif 3856 df-nul 4224 |
This theorem is referenced by: (None) |
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