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Mirrors > Home > MPE Home > Th. List > 2on | Structured version Visualization version GIF version |
Description: Ordinal 2 is an ordinal number. (Contributed by NM, 18-Feb-2004.) (Proof shortened by Andrew Salmon, 12-Aug-2011.) Avoid ax-un 7725. (Revised by BTernaryTau, 30-Nov-2024.) |
Ref | Expression |
---|---|
2on | ⊢ 2o ∈ On |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-2o 8467 | . 2 ⊢ 2o = suc 1o | |
2 | 1on 8478 | . . 3 ⊢ 1o ∈ On | |
3 | 2oex 8477 | . . . 4 ⊢ 2o ∈ V | |
4 | 1, 3 | eqeltrri 2831 | . . 3 ⊢ suc 1o ∈ V |
5 | sucexeloni 7797 | . . 3 ⊢ ((1o ∈ On ∧ suc 1o ∈ V) → suc 1o ∈ On) | |
6 | 2, 4, 5 | mp2an 691 | . 2 ⊢ suc 1o ∈ On |
7 | 1, 6 | eqeltri 2830 | 1 ⊢ 2o ∈ On |
Colors of variables: wff setvar class |
Syntax hints: ∈ wcel 2107 Vcvv 3475 Oncon0 6365 suc csuc 6367 1oc1o 8459 2oc2o 8460 |
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 ax-sep 5300 ax-nul 5307 ax-pr 5428 |
This theorem depends on definitions: df-bi 206 df-an 398 df-or 847 df-3or 1089 df-3an 1090 df-tru 1545 df-fal 1555 df-ex 1783 df-sb 2069 df-clab 2711 df-cleq 2725 df-clel 2811 df-ne 2942 df-ral 3063 df-rex 3072 df-rab 3434 df-v 3477 df-dif 3952 df-un 3954 df-in 3956 df-ss 3966 df-pss 3968 df-nul 4324 df-if 4530 df-pw 4605 df-sn 4630 df-pr 4632 df-op 4636 df-uni 4910 df-br 5150 df-opab 5212 df-tr 5267 df-eprel 5581 df-po 5589 df-so 5590 df-fr 5632 df-we 5634 df-ord 6368 df-on 6369 df-suc 6371 df-1o 8466 df-2o 8467 |
This theorem is referenced by: ord3 8483 3on 8484 ord2eln012 8497 o2p2e4 8541 oneo 8581 2onn 8641 nneob 8655 en3 9282 infxpenc 10013 infxpenc2 10017 mappwen 10107 pwdjuen 10176 ackbij1lem5 10219 sdom2en01 10297 fin1a2lem4 10398 fin1a2lem6 10400 xpsrnbas 17517 xpsadd 17520 xpsmul 17521 xpsvsca 17523 xpsle 17525 cat1 18047 xpsmnd 18665 xpsgrp 18942 efgval 19585 efgtf 19590 frgpcpbl 19627 frgp0 19628 frgpeccl 19629 frgpadd 19631 frgpmhm 19633 vrgpf 19636 vrgpinv 19637 frgpupf 19641 frgpup1 19643 frgpup2 19644 frgpup3lem 19645 frgpnabllem1 19741 frgpnabllem2 19742 xpsringd 20145 xpstopnlem1 23313 xpstps 23314 xpstopnlem2 23315 xpsxmetlem 23885 xpsdsval 23887 nofv 27160 sltres 27165 noextendgt 27173 nolesgn2ores 27175 nosepnelem 27182 nosepdmlem 27186 nolt02o 27198 nogt01o 27199 nosupno 27206 nosupbnd1lem3 27213 nosupbnd1 27217 nosupbnd2lem1 27218 nosupbnd2 27219 ssoninhaus 35333 onint1 35334 1oequni2o 36249 finxpreclem4 36275 pw2f1ocnv 41776 frlmpwfi 41840 omnord1 42055 oege2 42057 oenord1 42066 oaomoencom 42067 oenassex 42068 oenass 42069 omabs2 42082 oaltom 42156 omltoe 42158 2no 42188 nlim3 42195 tr3dom 42279 enrelmap 42748 xpsrngd 46680 |
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