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Mirrors > Home > MPE Home > Th. List > abn0 | Structured version Visualization version GIF version |
Description: Nonempty class abstraction. See also ab0 4336. (Contributed by NM, 26-Dec-1996.) (Proof shortened by Mario Carneiro, 11-Nov-2016.) |
Ref | Expression |
---|---|
abn0 | ⊢ ({𝑥 ∣ 𝜑} ≠ ∅ ↔ ∃𝑥𝜑) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | nfab1 2982 | . . 3 ⊢ Ⅎ𝑥{𝑥 ∣ 𝜑} | |
2 | 1 | n0f 4310 | . 2 ⊢ ({𝑥 ∣ 𝜑} ≠ ∅ ↔ ∃𝑥 𝑥 ∈ {𝑥 ∣ 𝜑}) |
3 | abid 2806 | . . 3 ⊢ (𝑥 ∈ {𝑥 ∣ 𝜑} ↔ 𝜑) | |
4 | 3 | exbii 1847 | . 2 ⊢ (∃𝑥 𝑥 ∈ {𝑥 ∣ 𝜑} ↔ ∃𝑥𝜑) |
5 | 2, 4 | bitri 277 | 1 ⊢ ({𝑥 ∣ 𝜑} ≠ ∅ ↔ ∃𝑥𝜑) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 208 ∃wex 1779 ∈ wcel 2113 {cab 2802 ≠ wne 3019 ∅c0 4294 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1795 ax-4 1809 ax-5 1910 ax-6 1969 ax-7 2014 ax-8 2115 ax-9 2123 ax-10 2144 ax-11 2160 ax-12 2176 ax-ext 2796 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-tru 1539 df-ex 1780 df-nf 1784 df-sb 2069 df-clab 2803 df-cleq 2817 df-clel 2896 df-nfc 2966 df-ne 3020 df-dif 3942 df-nul 4295 |
This theorem is referenced by: intexab 5245 iinexg 5247 relimasn 5955 inisegn0 5964 mapprc 8413 modom 8722 tz9.1c 9175 scott0 9318 scott0s 9320 cp 9323 karden 9327 acnrcl 9471 aceq3lem 9549 cff 9673 cff1 9683 cfss 9690 domtriomlem 9867 axdclem 9944 nqpr 10439 supadd 11612 supmul 11616 hashf1lem2 13817 hashf1 13818 mreiincl 16870 efgval 18846 efger 18847 birthdaylem3 25534 disjex 30345 disjexc 30346 mppsval 32823 mblfinlem3 34935 ismblfin 34937 itg2addnc 34950 sdclem1 35022 upbdrech 41578 |
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