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Theorem nnaordex 8254
 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 7573 . . . . . 6 (𝐵 ∈ ω → 𝐵 ∈ On)
21adantl 485 . . . . 5 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → 𝐵 ∈ On)
3 onelss 6204 . . . . 5 (𝐵 ∈ On → (𝐴𝐵𝐴𝐵))
42, 3syl 17 . . . 4 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵𝐴𝐵))
5 nnawordex 8253 . . . 4 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵 ↔ ∃𝑥 ∈ ω (𝐴 +o 𝑥) = 𝐵))
64, 5sylibd 242 . . 3 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵 → ∃𝑥 ∈ ω (𝐴 +o 𝑥) = 𝐵))
7 simplr 768 . . . . . . . . 9 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → 𝐴𝐵)
8 eleq2 2878 . . . . . . . . 9 ((𝐴 +o 𝑥) = 𝐵 → (𝐴 ∈ (𝐴 +o 𝑥) ↔ 𝐴𝐵))
97, 8syl5ibrcom 250 . . . . . . . 8 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → ((𝐴 +o 𝑥) = 𝐵𝐴 ∈ (𝐴 +o 𝑥)))
10 peano1 7588 . . . . . . . . . . . 12 ∅ ∈ ω
11 nnaord 8235 . . . . . . . . . . . 12 ((∅ ∈ ω ∧ 𝑥 ∈ ω ∧ 𝐴 ∈ ω) → (∅ ∈ 𝑥 ↔ (𝐴 +o ∅) ∈ (𝐴 +o 𝑥)))
1210, 11mp3an1 1445 . . . . . . . . . . 11 ((𝑥 ∈ ω ∧ 𝐴 ∈ ω) → (∅ ∈ 𝑥 ↔ (𝐴 +o ∅) ∈ (𝐴 +o 𝑥)))
1312ancoms 462 . . . . . . . . . 10 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → (∅ ∈ 𝑥 ↔ (𝐴 +o ∅) ∈ (𝐴 +o 𝑥)))
14 nna0 8220 . . . . . . . . . . . 12 (𝐴 ∈ ω → (𝐴 +o ∅) = 𝐴)
1514adantr 484 . . . . . . . . . . 11 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → (𝐴 +o ∅) = 𝐴)
1615eleq1d 2874 . . . . . . . . . 10 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → ((𝐴 +o ∅) ∈ (𝐴 +o 𝑥) ↔ 𝐴 ∈ (𝐴 +o 𝑥)))
1713, 16bitrd 282 . . . . . . . . 9 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → (∅ ∈ 𝑥𝐴 ∈ (𝐴 +o 𝑥)))
1817adantlr 714 . . . . . . . 8 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → (∅ ∈ 𝑥𝐴 ∈ (𝐴 +o 𝑥)))
199, 18sylibrd 262 . . . . . . 7 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → ((𝐴 +o 𝑥) = 𝐵 → ∅ ∈ 𝑥))
2019ancrd 555 . . . . . 6 (((𝐴 ∈ ω ∧ 𝐴𝐵) ∧ 𝑥 ∈ ω) → ((𝐴 +o 𝑥) = 𝐵 → (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵)))
2120reximdva 3233 . . . . 5 ((𝐴 ∈ ω ∧ 𝐴𝐵) → (∃𝑥 ∈ ω (𝐴 +o 𝑥) = 𝐵 → ∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵)))
2221ex 416 . . . 4 (𝐴 ∈ ω → (𝐴𝐵 → (∃𝑥 ∈ ω (𝐴 +o 𝑥) = 𝐵 → ∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵))))
2322adantr 484 . . 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 480 . . . . . 6 (((𝐴 ∈ ω ∧ 𝑥 ∈ ω) ∧ ∅ ∈ 𝑥) → 𝐴 ∈ (𝐴 +o 𝑥))
2625, 8syl5ibcom 248 . . . . 5 (((𝐴 ∈ ω ∧ 𝑥 ∈ ω) ∧ ∅ ∈ 𝑥) → ((𝐴 +o 𝑥) = 𝐵𝐴𝐵))
2726expimpd 457 . . . 4 ((𝐴 ∈ ω ∧ 𝑥 ∈ ω) → ((∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵) → 𝐴𝐵))
2827rexlimdva 3243 . . 3 (𝐴 ∈ ω → (∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵) → 𝐴𝐵))
2928adantr 484 . 2 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵) → 𝐴𝐵))
3024, 29impbid 215 1 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵 ↔ ∃𝑥 ∈ ω (∅ ∈ 𝑥 ∧ (𝐴 +o 𝑥) = 𝐵)))
 Colors of variables: wff setvar class Syntax hints:   → wi 4   ↔ wb 209   ∧ wa 399   = wceq 1538   ∈ wcel 2111  ∃wrex 3107   ⊆ wss 3881  ∅c0 4243  Oncon0 6162  (class class class)co 7140  ωcom 7567   +o coa 8089 This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-10 2142  ax-11 2158  ax-12 2175  ax-ext 2770  ax-sep 5168  ax-nul 5175  ax-pr 5296  ax-un 7448 This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3or 1085  df-3an 1086  df-tru 1541  df-ex 1782  df-nf 1786  df-sb 2070  df-mo 2598  df-eu 2629  df-clab 2777  df-cleq 2791  df-clel 2870  df-nfc 2938  df-ne 2988  df-ral 3111  df-rex 3112  df-reu 3113  df-rab 3115  df-v 3443  df-sbc 3721  df-csb 3829  df-dif 3884  df-un 3886  df-in 3888  df-ss 3898  df-pss 3900  df-nul 4244  df-if 4426  df-pw 4499  df-sn 4526  df-pr 4528  df-tp 4530  df-op 4532  df-uni 4802  df-int 4840  df-iun 4884  df-br 5032  df-opab 5094  df-mpt 5112  df-tr 5138  df-id 5426  df-eprel 5431  df-po 5439  df-so 5440  df-fr 5479  df-we 5481  df-xp 5526  df-rel 5527  df-cnv 5528  df-co 5529  df-dm 5530  df-rn 5531  df-res 5532  df-ima 5533  df-pred 6119  df-ord 6165  df-on 6166  df-lim 6167  df-suc 6168  df-iota 6286  df-fun 6329  df-fn 6330  df-f 6331  df-f1 6332  df-fo 6333  df-f1o 6334  df-fv 6335  df-ov 7143  df-oprab 7144  df-mpo 7145  df-om 7568  df-wrecs 7937  df-recs 7998  df-rdg 8036  df-oadd 8096 This theorem is referenced by:  ltexpi  10320
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