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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 4541 | . 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 209 = wceq 1543 ∈ wcel 2112 Vcvv 3398 {csn 4527 |
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-ext 2708 |
This theorem depends on definitions: df-bi 210 df-an 400 df-tru 1546 df-ex 1788 df-sb 2073 df-clab 2715 df-cleq 2728 df-clel 2809 df-sn 4528 |
This theorem is referenced by: velsn 4543 opthwiener 5382 brsnop 5390 opthprc 5598 dmsnn0 6050 dmsnopg 6056 cnvcnvsn 6062 snsn0non 6310 funconstss 6854 fniniseg 6858 fniniseg2 6860 fsn 6928 fconstfv 7006 eusvobj2 7184 fnse 7878 wfrlem14 8046 fisn 9021 axdc3lem4 10032 axdc4lem 10034 axcclem 10036 opelreal 10709 seqid3 13585 seqz 13589 1exp 13629 hashf1lem2 13987 fprodn0f 15516 imasaddfnlem 16987 initoid 17461 termoid 17462 0subm 18198 smndex1mgm 18288 smndex1n0mnd 18293 grpinvfval 18360 0subg 18522 0nsg 18539 sylow2alem2 18961 gsumval3 19246 gsumzaddlem 19260 kerf1ghm 19717 lsssn0 19938 r0cld 22589 alexsubALTlem2 22899 tgphaus 22968 isusp 23113 i1f1lem 24540 ig1pcl 25027 plyco0 25040 plyeq0lem 25058 plycj 25125 wilthlem2 25905 dchrfi 26090 snstriedgval 27083 incistruhgr 27124 1loopgrnb0 27544 umgr2v2enb1 27568 usgr2pthlem 27804 hsn0elch 29283 h1de2ctlem 29590 atomli 30417 suppiniseg 30694 1stpreimas 30712 gsummpt2d 30982 kerunit 31195 qqhval2lem 31597 qqhf 31602 qqhre 31636 esum2dlem 31726 eulerpartlemb 32001 bnj149 32522 subfacp1lem6 32814 xpord2pred 33472 xpord2ind 33474 xpord3pred 33478 ellimits 33898 bj-0nel1 34829 bj-isrvec 35148 poimirlem18 35481 poimirlem21 35484 poimirlem22 35485 poimirlem31 35494 poimirlem32 35495 itg2addnclem2 35515 ftc1anclem3 35538 0idl 35869 keridl 35876 smprngopr 35896 isdmn3 35918 ellkr 36789 diblss 38870 dihmeetlem4preN 39006 dihmeetlem13N 39019 sticksstones11 39781 0prjspnrel 40113 pw2f1ocnv 40503 fvnonrel 40822 snhesn 41012 unirnmapsn 42368 sge0fodjrnlem 43572 lindslinindsimp1 45414 |
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