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Mirrors > Home > MPE Home > Th. List > n0i | Structured version Visualization version GIF version |
Description: If a class has elements, then it is not empty. (Contributed by NM, 31-Dec-1993.) |
Ref | Expression |
---|---|
n0i | ⊢ (𝐵 ∈ 𝐴 → ¬ 𝐴 = ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | noel 4331 | . . 3 ⊢ ¬ 𝐵 ∈ ∅ | |
2 | eleq2 2823 | . . 3 ⊢ (𝐴 = ∅ → (𝐵 ∈ 𝐴 ↔ 𝐵 ∈ ∅)) | |
3 | 1, 2 | mtbiri 327 | . 2 ⊢ (𝐴 = ∅ → ¬ 𝐵 ∈ 𝐴) |
4 | 3 | con2i 139 | 1 ⊢ (𝐵 ∈ 𝐴 → ¬ 𝐴 = ∅) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 = wceq 1542 ∈ wcel 2107 ∅c0 4323 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1798 ax-4 1812 ax-5 1914 ax-6 1972 ax-7 2012 ax-8 2109 ax-9 2117 ax-ext 2704 |
This theorem depends on definitions: df-bi 206 df-an 398 df-tru 1545 df-fal 1555 df-ex 1783 df-sb 2069 df-clab 2711 df-cleq 2725 df-clel 2811 df-dif 3952 df-nul 4324 |
This theorem is referenced by: ne0i 4335 n0ii 4337 oprcl 4900 disjss3 5148 elfvdm 6929 mptrcl 7008 isomin 7334 ovrcl 7450 oalimcl 8560 omlimcl 8578 oaabs2 8648 ecexr 8708 elpmi 8840 elmapex 8842 pmresg 8864 pmsspw 8871 ixpssmap2g 8921 ixpssmapg 8922 resixpfo 8930 php3 9212 php3OLD 9224 cantnfp1lem2 9674 cantnflem1 9684 cnfcom2lem 9696 rankxplim2 9875 rankxplim3 9876 cardlim 9967 alephnbtwn 10066 ttukeylem5 10508 r1wunlim 10732 ssnn0fi 13950 ruclem13 16185 ramtub 16945 elbasfv 17150 elbasov 17151 restsspw 17377 homarcl 17978 grpidval 18580 odlem2 19407 efgrelexlema 19617 subcmn 19705 dvdsrval 20175 elocv 21221 pf1rcl 21868 matrcl 21912 0top 22486 ppttop 22510 pptbas 22511 restrcl 22661 ssrest 22680 iscnp2 22743 lmmo 22884 zfbas 23400 rnelfmlem 23456 isfcls 23513 isnghm 24240 iscau2 24794 itg2cnlem1 25279 itgsubstlem 25565 dchrrcl 26743 clwwlknnn 29286 0ringsubrg 32379 ssmxidllem 32589 eulerpartlemgvv 33375 indispconn 34225 cvmtop1 34251 cvmtop2 34252 mrsub0 34507 mrsubf 34508 mrsubccat 34509 mrsubcn 34510 mrsubco 34512 mrsubvrs 34513 msubf 34523 mclsrcl 34552 funpartlem 34914 tailfb 35262 nlpineqsn 36289 atbase 38159 llnbase 38380 lplnbase 38405 lvolbase 38449 osumcllem4N 38830 pexmidlem1N 38841 lhpbase 38869 mapco2g 41452 wepwsolem 41784 onov0suclim 42024 uneqsn 42776 ssfiunibd 44019 hoicvr 45264 0nelsetpreimafv 46058 |
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