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Mirrors > Home > MPE Home > Th. List > elsn | Structured version Visualization version GIF version |
Description: There is exactly one element in a singleton. Exercise 2 of [TakeutiZaring] p. 15. (Contributed by NM, 13-Sep-1995.) |
Ref | Expression |
---|---|
elsn.1 | ⊢ 𝐴 ∈ V |
Ref | Expression |
---|---|
elsn | ⊢ (𝐴 ∈ {𝐵} ↔ 𝐴 = 𝐵) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elsn.1 | . 2 ⊢ 𝐴 ∈ V | |
2 | elsng 4191 | . 2 ⊢ (𝐴 ∈ V → (𝐴 ∈ {𝐵} ↔ 𝐴 = 𝐵)) | |
3 | 1, 2 | ax-mp 5 | 1 ⊢ (𝐴 ∈ {𝐵} ↔ 𝐴 = 𝐵) |
Colors of variables: wff setvar class |
Syntax hints: ↔ wb 196 = wceq 1483 ∈ wcel 1990 Vcvv 3200 {csn 4177 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1722 ax-4 1737 ax-5 1839 ax-6 1888 ax-7 1935 ax-9 1999 ax-10 2019 ax-11 2034 ax-12 2047 ax-13 2246 ax-ext 2602 |
This theorem depends on definitions: df-bi 197 df-or 385 df-an 386 df-tru 1486 df-ex 1705 df-nf 1710 df-sb 1881 df-clab 2609 df-cleq 2615 df-clel 2618 df-nfc 2753 df-v 3202 df-sn 4178 |
This theorem is referenced by: velsn 4193 opthwiener 4976 opthprc 5167 dmsnn0 5600 dmsnopg 5606 cnvcnvsn 5612 snsn0non 5846 funconstss 6335 fniniseg 6338 fniniseg2 6340 fsn 6402 fconstfv 6476 eusvobj2 6643 fnse 7294 wfrlem14 7428 mapdm0 7872 fisn 8333 axdc3lem4 9275 axdc4lem 9277 axcclem 9279 opelreal 9951 seqid3 12845 seqz 12849 1exp 12889 hashf1lem2 13240 fprodn0f 14722 imasaddfnlem 16188 initoid 16655 termoid 16656 0subg 17619 0nsg 17639 sylow2alem2 18033 gsumval3 18308 gsumzaddlem 18321 kerf1hrm 18743 lsssn0 18948 r0cld 21541 alexsubALTlem2 21852 tgphaus 21920 isusp 22065 i1f1lem 23456 ig1pcl 23935 plyco0 23948 plyeq0lem 23966 plycj 24033 wilthlem2 24795 dchrfi 24980 snstriedgval 25930 incistruhgr 25974 1loopgrnb0 26398 umgr2v2enb1 26422 usgr2pthlem 26659 hsn0elch 28105 h1de2ctlem 28414 atomli 29241 1stpreimas 29483 gsummpt2d 29781 kerunit 29823 qqhval2lem 30025 qqhf 30030 qqhre 30064 esum2dlem 30154 eulerpartlemb 30430 bnj149 30945 subfacp1lem6 31167 ellimits 32017 bj-0nel1 32940 poimirlem18 33427 poimirlem21 33430 poimirlem22 33431 poimirlem31 33440 poimirlem32 33441 itg2addnclem2 33462 ftc1anclem3 33487 0idl 33824 keridl 33831 smprngopr 33851 isdmn3 33873 ellkr 34376 diblss 36459 dihmeetlem4preN 36595 dihmeetlem13N 36608 pw2f1ocnv 37604 fvnonrel 37903 snhesn 38080 unirnmapsn 39406 sge0fodjrnlem 40633 lindslinindsimp1 42246 |
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