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Mirrors > Home > MPE Home > Th. List > 1onn | Structured version Visualization version GIF version |
Description: The ordinal 1 is a natural number. For a shorter proof using Peano's postulates that depends on ax-un 7753, see 1onnALT 8677. Lemma 2.2 of [Schloeder] p. 4. (Contributed by NM, 29-Oct-1995.) Avoid ax-un 7753. (Revised by BTernaryTau, 1-Dec-2024.) |
Ref | Expression |
---|---|
1onn | ⊢ 1o ∈ ω |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 1on 8516 | . 2 ⊢ 1o ∈ On | |
2 | 1ellim 8534 | . . 3 ⊢ (Lim 𝑥 → 1o ∈ 𝑥) | |
3 | 2 | ax-gen 1791 | . 2 ⊢ ∀𝑥(Lim 𝑥 → 1o ∈ 𝑥) |
4 | elom 7889 | . 2 ⊢ (1o ∈ ω ↔ (1o ∈ On ∧ ∀𝑥(Lim 𝑥 → 1o ∈ 𝑥))) | |
5 | 1, 3, 4 | mpbir2an 711 | 1 ⊢ 1o ∈ ω |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ∀wal 1534 ∈ wcel 2105 Oncon0 6385 Lim wlim 6386 ωcom 7886 1oc1o 8497 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1791 ax-4 1805 ax-5 1907 ax-6 1964 ax-7 2004 ax-8 2107 ax-9 2115 ax-ext 2705 ax-sep 5301 ax-nul 5311 ax-pr 5437 |
This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-3or 1087 df-3an 1088 df-tru 1539 df-fal 1549 df-ex 1776 df-sb 2062 df-clab 2712 df-cleq 2726 df-clel 2813 df-ne 2938 df-ral 3059 df-rex 3068 df-rab 3433 df-v 3479 df-dif 3965 df-un 3967 df-in 3969 df-ss 3979 df-pss 3982 df-nul 4339 df-if 4531 df-pw 4606 df-sn 4631 df-pr 4633 df-op 4637 df-uni 4912 df-br 5148 df-opab 5210 df-tr 5265 df-eprel 5588 df-po 5596 df-so 5597 df-fr 5640 df-we 5642 df-ord 6388 df-on 6389 df-lim 6390 df-suc 6391 df-om 7887 df-1o 8504 |
This theorem is referenced by: 2onnALT 8679 1one2o 8682 oaabs2 8685 omabs 8687 nnm2 8689 nnneo 8691 nneob 8692 snfi 9081 snfiOLD 9082 snnen2oOLD 9261 1sdom2ALT 9274 1sdomOLD 9282 unxpdom2 9287 en1eqsnOLD 9306 wofib 9582 oancom 9688 cnfcom3clem 9742 ssttrcl 9752 ttrcltr 9753 djurf1o 9950 card1 10005 pm54.43lem 10037 en2eleq 10045 en2other2 10046 infxpenlem 10050 infxpenc2lem1 10056 sdom2en01 10339 cfpwsdom 10621 canthp1lem2 10690 gchdju1 10693 pwxpndom2 10702 pwdjundom 10704 1pi 10920 1lt2pi 10942 indpi 10944 hash2 14440 hash1snb 14454 fnpr2o 17603 fvpr1o 17606 f1otrspeq 19479 pmtrf 19487 pmtrmvd 19488 pmtrfinv 19493 lt6abl 19927 isnzr2 20534 frgpcyg 21609 vr1cl 22234 ply1coe 22317 isppw 27171 pw2bday 28432 bnj906 34922 sat1el2xp 35363 satfv1fvfmla1 35407 satefvfmla1 35409 ex-sategoelelomsuc 35410 ex-sategoelel12 35411 finxpreclem1 37371 finxpreclem2 37372 finxp1o 37374 finxpreclem4 37376 finxp2o 37381 domalom 37386 onexoegt 43232 1oaomeqom 43282 oaabsb 43283 omnord1ex 43293 oaomoencom 43306 cantnftermord 43309 cantnf2 43314 omabs2 43321 omcl2 43322 1finon 43438 finona1cl 43442 1iscard 43531 |
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