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Mirrors > Home > MPE Home > Th. List > 0fi | Structured version Visualization version GIF version |
Description: The empty set is finite. (Contributed by FL, 14-Jul-2008.) Avoid ax-10 2141, ax-un 7770. (Revised by BTernaryTau, 13-Jan-2025.) |
Ref | Expression |
---|---|
0fi | ⊢ ∅ ∈ Fin |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | peano1 7927 | . . 3 ⊢ ∅ ∈ ω | |
2 | eqid 2740 | . . . 4 ⊢ ∅ = ∅ | |
3 | en0 9078 | . . . 4 ⊢ (∅ ≈ ∅ ↔ ∅ = ∅) | |
4 | 2, 3 | mpbir 231 | . . 3 ⊢ ∅ ≈ ∅ |
5 | breq2 5170 | . . . 4 ⊢ (𝑥 = ∅ → (∅ ≈ 𝑥 ↔ ∅ ≈ ∅)) | |
6 | 5 | rspcev 3635 | . . 3 ⊢ ((∅ ∈ ω ∧ ∅ ≈ ∅) → ∃𝑥 ∈ ω ∅ ≈ 𝑥) |
7 | 1, 4, 6 | mp2an 691 | . 2 ⊢ ∃𝑥 ∈ ω ∅ ≈ 𝑥 |
8 | isfi 9036 | . 2 ⊢ (∅ ∈ Fin ↔ ∃𝑥 ∈ ω ∅ ≈ 𝑥) | |
9 | 7, 8 | mpbir 231 | 1 ⊢ ∅ ∈ Fin |
Colors of variables: wff setvar class |
Syntax hints: = wceq 1537 ∈ wcel 2108 ∃wrex 3076 ∅c0 4352 class class class wbr 5166 ωcom 7903 ≈ cen 9000 Fincfn 9003 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1793 ax-4 1807 ax-5 1909 ax-6 1967 ax-7 2007 ax-8 2110 ax-9 2118 ax-12 2178 ax-ext 2711 ax-sep 5317 ax-nul 5324 ax-pr 5447 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 847 df-3or 1088 df-3an 1089 df-tru 1540 df-fal 1550 df-ex 1778 df-sb 2065 df-mo 2543 df-clab 2718 df-cleq 2732 df-clel 2819 df-ne 2947 df-ral 3068 df-rex 3077 df-rab 3444 df-v 3490 df-dif 3979 df-un 3981 df-in 3983 df-ss 3993 df-pss 3996 df-nul 4353 df-if 4549 df-pw 4624 df-sn 4649 df-pr 4651 df-op 4655 df-uni 4932 df-br 5167 df-opab 5229 df-tr 5284 df-id 5593 df-eprel 5599 df-po 5607 df-so 5608 df-fr 5652 df-we 5654 df-xp 5706 df-rel 5707 df-cnv 5708 df-co 5709 df-dm 5710 df-rn 5711 df-ord 6398 df-on 6399 df-lim 6400 df-fun 6575 df-fn 6576 df-f 6577 df-f1 6578 df-fo 6579 df-f1o 6580 df-om 7904 df-en 9004 df-fin 9007 |
This theorem is referenced by: snfi 9109 ssfi 9240 cnvfi 9243 fnfi 9244 nneneq 9272 nfielex 9335 imafiOLD 9382 xpfiOLD 9387 fodomfib 9397 iunfi 9411 fczfsuppd 9455 fsuppun 9456 0fsupp 9459 r1fin 9842 acndom 10120 numwdom 10128 ackbij1lem18 10305 sdom2en01 10371 fin23lem26 10394 isfin1-3 10455 gchxpidm 10738 fzfi 14023 fzofi 14025 hasheq0 14412 hashxp 14483 lcmf0 16681 0hashbc 17054 acsfn0 17718 isdrs2 18376 fpwipodrs 18610 symgfisg 19510 dsmm0cl 21783 mplsubg 22045 mpllss 22046 psrbag0 22109 mat0dimbas0 22493 mat0dim0 22494 mat0dimid 22495 mat0dimscm 22496 mat0dimcrng 22497 mat0scmat 22565 mavmul0 22579 mavmul0g 22580 mdet0pr 22619 m1detdiag 22624 d0mat2pmat 22765 chpmat0d 22861 fctop 23032 cmpfi 23437 bwth 23439 comppfsc 23561 ptbasid 23604 cfinfil 23922 ufinffr 23958 fin1aufil 23961 alexsubALTlem2 24077 alexsubALTlem4 24079 ptcmplem2 24082 tsmsfbas 24157 xrge0gsumle 24874 xrge0tsms 24875 fta1 26368 uhgr0edgfi 29275 fusgrfisbase 29363 vtxdg0e 29510 wwlksnfi 29939 mptiffisupp 32705 hashxpe 32814 xrge0tsmsd 33041 esumnul 34012 esum0 34013 esumcst 34027 esumsnf 34028 esumpcvgval 34042 sibf0 34299 eulerpartlemt 34336 derang0 35137 topdifinffinlem 37313 matunitlindf 37578 0totbnd 37733 heiborlem6 37776 mzpcompact2lem 42707 rp-isfinite6 43480 0pwfi 44961 fouriercn 46153 rrxtopn0 46214 salexct 46255 sge0rnn0 46289 sge00 46297 sge0sn 46300 ovn0val 46471 ovn02 46489 hoidmv0val 46504 hoidmvle 46521 hoiqssbl 46546 von0val 46592 vonhoire 46593 vonioo 46603 vonicc 46606 vonsn 46612 lcoc0 48151 lco0 48156 |
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