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Theorem nnaordex 8253
Description: Equivalence for ordering. Compare Exercise 23 of [Enderton] p. 88. (Contributed by NM, 5-Dec-1995.) (Revised by Mario Carneiro, 15-Nov-2014.)
Assertion
Ref Expression
nnaordex ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵 ↔ ∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵)))
Distinct variable groups:   𝑥,𝐴   𝑥,𝐵

Proof of Theorem nnaordex
StepHypRef Expression
1 nnon 7575 . . . . . 6 (𝐵 ∈ ω → 𝐵 ∈ On)
21adantl 482 . . . . 5 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → 𝐵 ∈ On)
3 onelss 6226 . . . . 5 (𝐵 ∈ On → (𝐴𝐵𝐴𝐵))
42, 3syl 17 . . . 4 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵𝐴𝐵))
5 nnawordex 8252 . . . 4 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵 ↔ ∃𝑥 ∈ ω (𝐴 +o 𝑥) = 𝐵))
64, 5sylibd 240 . . 3 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵 → ∃𝑥 ∈ ω (𝐴 +o 𝑥) = 𝐵))
7 simplr 765 . . . . . . . . 9 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → 𝐴𝐵)
8 eleq2 2898 . . . . . . . . 9 ((𝐴 +o 𝑥) = 𝐵 → (𝐴 ∈ (𝐴 +o 𝑥) ↔ 𝐴𝐵))
97, 8syl5ibrcom 248 . . . . . . . 8 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → ((𝐴 +o 𝑥) = 𝐵𝐴 ∈ (𝐴 +o 𝑥)))
10 peano1 7590 . . . . . . . . . . . 12 ∅ ∈ ω
11 nnaord 8234 . . . . . . . . . . . 12 ((∅ ∈ ω ∧ 𝑥 ∈ ω ∧ 𝐴 ∈ ω) → (∅ ∈ 𝑥 ↔ (𝐴 +o ∅) ∈ (𝐴 +o 𝑥)))
1210, 11mp3an1 1439 . . . . . . . . . . 11 ((𝑥 ∈ ω ∧ 𝐴 ∈ ω) → (∅ ∈ 𝑥 ↔ (𝐴 +o ∅) ∈ (𝐴 +o 𝑥)))
1312ancoms 459 . . . . . . . . . 10 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → (∅ ∈ 𝑥 ↔ (𝐴 +o ∅) ∈ (𝐴 +o 𝑥)))
14 nna0 8219 . . . . . . . . . . . 12 (𝐴 ∈ ω → (𝐴 +o ∅) = 𝐴)
1514adantr 481 . . . . . . . . . . 11 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → (𝐴 +o ∅) = 𝐴)
1615eleq1d 2894 . . . . . . . . . 10 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → ((𝐴 +o ∅) ∈ (𝐴 +o 𝑥) ↔ 𝐴 ∈ (𝐴 +o 𝑥)))
1713, 16bitrd 280 . . . . . . . . 9 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → (∅ ∈ 𝑥𝐴 ∈ (𝐴 +o 𝑥)))
1817adantlr 711 . . . . . . . 8 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → (∅ ∈ 𝑥𝐴 ∈ (𝐴 +o 𝑥)))
199, 18sylibrd 260 . . . . . . 7 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → ((𝐴 +o 𝑥) = 𝐵 → ∅ ∈ 𝑥))
2019ancrd 552 . . . . . 6 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → ((𝐴 +o 𝑥) = 𝐵 → (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵)))
2120reximdva 3271 . . . . 5 ((𝐴 ∈ ω ∧ 𝐴𝐵) → (∃𝑥 ∈ ω (𝐴 +o 𝑥) = 𝐵 → ∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵)))
2221ex 413 . . . 4 (𝐴 ∈ ω → (𝐴𝐵 → (∃𝑥 ∈ ω (𝐴 +o 𝑥) = 𝐵 → ∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵))))
2322adantr 481 . . 3 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵 → (∃𝑥 ∈ ω (𝐴 +o 𝑥) = 𝐵 → ∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵))))
246, 23mpdd 43 . 2 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵 → ∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵)))
2517biimpa 477 . . . . . 6 (((𝐴 ∈ ω ∧ 𝑥 ∈ ω) ∧ ∅ ∈ 𝑥) → 𝐴 ∈ (𝐴 +o 𝑥))
2625, 8syl5ibcom 246 . . . . 5 (((𝐴 ∈ ω ∧ 𝑥 ∈ ω) ∧ ∅ ∈ 𝑥) → ((𝐴 +o 𝑥) = 𝐵𝐴𝐵))
2726expimpd 454 . . . 4 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → ((∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵) → 𝐴𝐵))
2827rexlimdva 3281 . . 3 (𝐴 ∈ ω → (∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵) → 𝐴𝐵))
2928adantr 481 . 2 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵) → 𝐴𝐵))
3024, 29impbid 213 1 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵 ↔ ∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵)))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 207  wa 396   = wceq 1528  wcel 2105  wrex 3136  wss 3933  c0 4288  Oncon0 6184  (class class class)co 7145  ωcom 7569   +o coa 8088
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1787  ax-4 1801  ax-5 1902  ax-6 1961  ax-7 2006  ax-8 2107  ax-9 2115  ax-10 2136  ax-11 2151  ax-12 2167  ax-ext 2790  ax-sep 5194  ax-nul 5201  ax-pow 5257  ax-pr 5320  ax-un 7450
This theorem depends on definitions:  df-bi 208  df-an 397  df-or 842  df-3or 1080  df-3an 1081  df-tru 1531  df-ex 1772  df-nf 1776  df-sb 2061  df-mo 2615  df-eu 2647  df-clab 2797  df-cleq 2811  df-clel 2890  df-nfc 2960  df-ne 3014  df-ral 3140  df-rex 3141  df-reu 3142  df-rab 3144  df-v 3494  df-sbc 3770  df-csb 3881  df-dif 3936  df-un 3938  df-in 3940  df-ss 3949  df-pss 3951  df-nul 4289  df-if 4464  df-pw 4537  df-sn 4558  df-pr 4560  df-tp 4562  df-op 4564  df-uni 4831  df-int 4868  df-iun 4912  df-br 5058  df-opab 5120  df-mpt 5138  df-tr 5164  df-id 5453  df-eprel 5458  df-po 5467  df-so 5468  df-fr 5507  df-we 5509  df-xp 5554  df-rel 5555  df-cnv 5556  df-co 5557  df-dm 5558  df-rn 5559  df-res 5560  df-ima 5561  df-pred 6141  df-ord 6187  df-on 6188  df-lim 6189  df-suc 6190  df-iota 6307  df-fun 6350  df-fn 6351  df-f 6352  df-f1 6353  df-fo 6354  df-f1o 6355  df-fv 6356  df-ov 7148  df-oprab 7149  df-mpo 7150  df-om 7570  df-wrecs 7936  df-recs 7997  df-rdg 8035  df-oadd 8095
This theorem is referenced by:  ltexpi  10312
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