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Theorem nneneq 9215
Description: Two equinumerous natural numbers are equal. Proposition 10.20 of [TakeutiZaring] p. 90 and its converse. Also compare Corollary 6E of [Enderton] p. 136. (Contributed by NM, 28-May-1998.) Avoid ax-pow 5363. (Revised by BTernaryTau, 11-Nov-2024.)
Assertion
Ref Expression
nneneq ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵𝐴 = 𝐵))

Proof of Theorem nneneq
Dummy variables 𝑥 𝑦 𝑧 𝑤 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 breq1 5151 . . . . . 6 (𝑥 = ∅ → (𝑥𝑧 ↔ ∅ ≈ 𝑧))
2 eqeq1 2735 . . . . . 6 (𝑥 = ∅ → (𝑥 = 𝑧 ↔ ∅ = 𝑧))
31, 2imbi12d 344 . . . . 5 (𝑥 = ∅ → ((𝑥𝑧𝑥 = 𝑧) ↔ (∅ ≈ 𝑧 → ∅ = 𝑧)))
43ralbidv 3176 . . . 4 (𝑥 = ∅ → (∀𝑧 ∈ ω (𝑥𝑧𝑥 = 𝑧) ↔ ∀𝑧 ∈ ω (∅ ≈ 𝑧 → ∅ = 𝑧)))
5 breq1 5151 . . . . . 6 (𝑥 = 𝑦 → (𝑥𝑧𝑦𝑧))
6 eqeq1 2735 . . . . . 6 (𝑥 = 𝑦 → (𝑥 = 𝑧𝑦 = 𝑧))
75, 6imbi12d 344 . . . . 5 (𝑥 = 𝑦 → ((𝑥𝑧𝑥 = 𝑧) ↔ (𝑦𝑧𝑦 = 𝑧)))
87ralbidv 3176 . . . 4 (𝑥 = 𝑦 → (∀𝑧 ∈ ω (𝑥𝑧𝑥 = 𝑧) ↔ ∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧)))
9 breq1 5151 . . . . . 6 (𝑥 = suc 𝑦 → (𝑥𝑧 ↔ suc 𝑦𝑧))
10 eqeq1 2735 . . . . . 6 (𝑥 = suc 𝑦 → (𝑥 = 𝑧 ↔ suc 𝑦 = 𝑧))
119, 10imbi12d 344 . . . . 5 (𝑥 = suc 𝑦 → ((𝑥𝑧𝑥 = 𝑧) ↔ (suc 𝑦𝑧 → suc 𝑦 = 𝑧)))
1211ralbidv 3176 . . . 4 (𝑥 = suc 𝑦 → (∀𝑧 ∈ ω (𝑥𝑧𝑥 = 𝑧) ↔ ∀𝑧 ∈ ω (suc 𝑦𝑧 → suc 𝑦 = 𝑧)))
13 breq1 5151 . . . . . 6 (𝑥 = 𝐴 → (𝑥𝑧𝐴𝑧))
14 eqeq1 2735 . . . . . 6 (𝑥 = 𝐴 → (𝑥 = 𝑧𝐴 = 𝑧))
1513, 14imbi12d 344 . . . . 5 (𝑥 = 𝐴 → ((𝑥𝑧𝑥 = 𝑧) ↔ (𝐴𝑧𝐴 = 𝑧)))
1615ralbidv 3176 . . . 4 (𝑥 = 𝐴 → (∀𝑧 ∈ ω (𝑥𝑧𝑥 = 𝑧) ↔ ∀𝑧 ∈ ω (𝐴𝑧𝐴 = 𝑧)))
17 0fin 9177 . . . . . . 7 ∅ ∈ Fin
18 ensymfib 9193 . . . . . . 7 (∅ ∈ Fin → (∅ ≈ 𝑧𝑧 ≈ ∅))
1917, 18ax-mp 5 . . . . . 6 (∅ ≈ 𝑧𝑧 ≈ ∅)
20 en0 9019 . . . . . . 7 (𝑧 ≈ ∅ ↔ 𝑧 = ∅)
21 eqcom 2738 . . . . . . 7 (𝑧 = ∅ ↔ ∅ = 𝑧)
2220, 21bitri 275 . . . . . 6 (𝑧 ≈ ∅ ↔ ∅ = 𝑧)
2319, 22sylbb 218 . . . . 5 (∅ ≈ 𝑧 → ∅ = 𝑧)
2423rgenw 3064 . . . 4 𝑧 ∈ ω (∅ ≈ 𝑧 → ∅ = 𝑧)
25 nn0suc 7890 . . . . . . 7 (𝑤 ∈ ω → (𝑤 = ∅ ∨ ∃𝑧 ∈ ω 𝑤 = suc 𝑧))
26 en0 9019 . . . . . . . . . . . 12 (suc 𝑦 ≈ ∅ ↔ suc 𝑦 = ∅)
27 breq2 5152 . . . . . . . . . . . . 13 (𝑤 = ∅ → (suc 𝑦𝑤 ↔ suc 𝑦 ≈ ∅))
28 eqeq2 2743 . . . . . . . . . . . . 13 (𝑤 = ∅ → (suc 𝑦 = 𝑤 ↔ suc 𝑦 = ∅))
2927, 28bibi12d 345 . . . . . . . . . . . 12 (𝑤 = ∅ → ((suc 𝑦𝑤 ↔ suc 𝑦 = 𝑤) ↔ (suc 𝑦 ≈ ∅ ↔ suc 𝑦 = ∅)))
3026, 29mpbiri 258 . . . . . . . . . . 11 (𝑤 = ∅ → (suc 𝑦𝑤 ↔ suc 𝑦 = 𝑤))
3130biimpd 228 . . . . . . . . . 10 (𝑤 = ∅ → (suc 𝑦𝑤 → suc 𝑦 = 𝑤))
3231a1i 11 . . . . . . . . 9 ((𝑦 ∈ ω ∧ ∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧)) → (𝑤 = ∅ → (suc 𝑦𝑤 → suc 𝑦 = 𝑤)))
33 nfv 1916 . . . . . . . . . . 11 𝑧 𝑦 ∈ ω
34 nfra1 3280 . . . . . . . . . . 11 𝑧𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧)
3533, 34nfan 1901 . . . . . . . . . 10 𝑧(𝑦 ∈ ω ∧ ∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧))
36 nfv 1916 . . . . . . . . . 10 𝑧(suc 𝑦𝑤 → suc 𝑦 = 𝑤)
37 vex 3477 . . . . . . . . . . . . . . . . 17 𝑦 ∈ V
3837phplem2 9214 . . . . . . . . . . . . . . . 16 ((𝑦 ∈ ω ∧ 𝑧 ∈ ω) → (suc 𝑦 ≈ suc 𝑧𝑦𝑧))
3938imim1d 82 . . . . . . . . . . . . . . 15 ((𝑦 ∈ ω ∧ 𝑧 ∈ ω) → ((𝑦𝑧𝑦 = 𝑧) → (suc 𝑦 ≈ suc 𝑧𝑦 = 𝑧)))
4039ex 412 . . . . . . . . . . . . . 14 (𝑦 ∈ ω → (𝑧 ∈ ω → ((𝑦𝑧𝑦 = 𝑧) → (suc 𝑦 ≈ suc 𝑧𝑦 = 𝑧))))
4140a2d 29 . . . . . . . . . . . . 13 (𝑦 ∈ ω → ((𝑧 ∈ ω → (𝑦𝑧𝑦 = 𝑧)) → (𝑧 ∈ ω → (suc 𝑦 ≈ suc 𝑧𝑦 = 𝑧))))
42 rsp 3243 . . . . . . . . . . . . 13 (∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧) → (𝑧 ∈ ω → (𝑦𝑧𝑦 = 𝑧)))
4341, 42impel 505 . . . . . . . . . . . 12 ((𝑦 ∈ ω ∧ ∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧)) → (𝑧 ∈ ω → (suc 𝑦 ≈ suc 𝑧𝑦 = 𝑧)))
44 suceq 6430 . . . . . . . . . . . 12 (𝑦 = 𝑧 → suc 𝑦 = suc 𝑧)
4543, 44syl8 76 . . . . . . . . . . 11 ((𝑦 ∈ ω ∧ ∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧)) → (𝑧 ∈ ω → (suc 𝑦 ≈ suc 𝑧 → suc 𝑦 = suc 𝑧)))
46 breq2 5152 . . . . . . . . . . . . 13 (𝑤 = suc 𝑧 → (suc 𝑦𝑤 ↔ suc 𝑦 ≈ suc 𝑧))
47 eqeq2 2743 . . . . . . . . . . . . 13 (𝑤 = suc 𝑧 → (suc 𝑦 = 𝑤 ↔ suc 𝑦 = suc 𝑧))
4846, 47imbi12d 344 . . . . . . . . . . . 12 (𝑤 = suc 𝑧 → ((suc 𝑦𝑤 → suc 𝑦 = 𝑤) ↔ (suc 𝑦 ≈ suc 𝑧 → suc 𝑦 = suc 𝑧)))
4948biimprcd 249 . . . . . . . . . . 11 ((suc 𝑦 ≈ suc 𝑧 → suc 𝑦 = suc 𝑧) → (𝑤 = suc 𝑧 → (suc 𝑦𝑤 → suc 𝑦 = 𝑤)))
5045, 49syl6 35 . . . . . . . . . 10 ((𝑦 ∈ ω ∧ ∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧)) → (𝑧 ∈ ω → (𝑤 = suc 𝑧 → (suc 𝑦𝑤 → suc 𝑦 = 𝑤))))
5135, 36, 50rexlimd 3262 . . . . . . . . 9 ((𝑦 ∈ ω ∧ ∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧)) → (∃𝑧 ∈ ω 𝑤 = suc 𝑧 → (suc 𝑦𝑤 → suc 𝑦 = 𝑤)))
5232, 51jaod 856 . . . . . . . 8 ((𝑦 ∈ ω ∧ ∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧)) → ((𝑤 = ∅ ∨ ∃𝑧 ∈ ω 𝑤 = suc 𝑧) → (suc 𝑦𝑤 → suc 𝑦 = 𝑤)))
5352ex 412 . . . . . . 7 (𝑦 ∈ ω → (∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧) → ((𝑤 = ∅ ∨ ∃𝑧 ∈ ω 𝑤 = suc 𝑧) → (suc 𝑦𝑤 → suc 𝑦 = 𝑤))))
5425, 53syl7 74 . . . . . 6 (𝑦 ∈ ω → (∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧) → (𝑤 ∈ ω → (suc 𝑦𝑤 → suc 𝑦 = 𝑤))))
5554ralrimdv 3151 . . . . 5 (𝑦 ∈ ω → (∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧) → ∀𝑤 ∈ ω (suc 𝑦𝑤 → suc 𝑦 = 𝑤)))
56 breq2 5152 . . . . . . 7 (𝑤 = 𝑧 → (suc 𝑦𝑤 ↔ suc 𝑦𝑧))
57 eqeq2 2743 . . . . . . 7 (𝑤 = 𝑧 → (suc 𝑦 = 𝑤 ↔ suc 𝑦 = 𝑧))
5856, 57imbi12d 344 . . . . . 6 (𝑤 = 𝑧 → ((suc 𝑦𝑤 → suc 𝑦 = 𝑤) ↔ (suc 𝑦𝑧 → suc 𝑦 = 𝑧)))
5958cbvralvw 3233 . . . . 5 (∀𝑤 ∈ ω (suc 𝑦𝑤 → suc 𝑦 = 𝑤) ↔ ∀𝑧 ∈ ω (suc 𝑦𝑧 → suc 𝑦 = 𝑧))
6055, 59imbitrdi 250 . . . 4 (𝑦 ∈ ω → (∀𝑧 ∈ ω (𝑦𝑧𝑦 = 𝑧) → ∀𝑧 ∈ ω (suc 𝑦𝑧 → suc 𝑦 = 𝑧)))
614, 8, 12, 16, 24, 60finds 7893 . . 3 (𝐴 ∈ ω → ∀𝑧 ∈ ω (𝐴𝑧𝐴 = 𝑧))
62 breq2 5152 . . . . 5 (𝑧 = 𝐵 → (𝐴𝑧𝐴𝐵))
63 eqeq2 2743 . . . . 5 (𝑧 = 𝐵 → (𝐴 = 𝑧𝐴 = 𝐵))
6462, 63imbi12d 344 . . . 4 (𝑧 = 𝐵 → ((𝐴𝑧𝐴 = 𝑧) ↔ (𝐴𝐵𝐴 = 𝐵)))
6564rspcv 3608 . . 3 (𝐵 ∈ ω → (∀𝑧 ∈ ω (𝐴𝑧𝐴 = 𝑧) → (𝐴𝐵𝐴 = 𝐵)))
6661, 65mpan9 506 . 2 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵𝐴 = 𝐵))
67 enrefnn 9053 . . . 4 (𝐴 ∈ ω → 𝐴𝐴)
68 breq2 5152 . . . 4 (𝐴 = 𝐵 → (𝐴𝐴𝐴𝐵))
6967, 68syl5ibcom 244 . . 3 (𝐴 ∈ ω → (𝐴 = 𝐵𝐴𝐵))
7069adantr 480 . 2 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴 = 𝐵𝐴𝐵))
7166, 70impbid 211 1 ((𝐴 ∈ ω ∧ 𝐵 ∈ ω) → (𝐴𝐵𝐴 = 𝐵))
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 205  wa 395  wo 844   = wceq 1540  wcel 2105  wral 3060  wrex 3069  c0 4322   class class class wbr 5148  suc csuc 6366  ωcom 7859  cen 8942  Fincfn 8945
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1796  ax-4 1810  ax-5 1912  ax-6 1970  ax-7 2010  ax-8 2107  ax-9 2115  ax-10 2136  ax-11 2153  ax-12 2170  ax-ext 2702  ax-sep 5299  ax-nul 5306  ax-pr 5427  ax-un 7729
This theorem depends on definitions:  df-bi 206  df-an 396  df-or 845  df-3or 1087  df-3an 1088  df-tru 1543  df-fal 1553  df-ex 1781  df-nf 1785  df-sb 2067  df-mo 2533  df-eu 2562  df-clab 2709  df-cleq 2723  df-clel 2809  df-nfc 2884  df-ne 2940  df-ral 3061  df-rex 3070  df-reu 3376  df-rab 3432  df-v 3475  df-sbc 3778  df-csb 3894  df-dif 3951  df-un 3953  df-in 3955  df-ss 3965  df-pss 3967  df-nul 4323  df-if 4529  df-pw 4604  df-sn 4629  df-pr 4631  df-op 4635  df-uni 4909  df-br 5149  df-opab 5211  df-mpt 5232  df-tr 5266  df-id 5574  df-eprel 5580  df-po 5588  df-so 5589  df-fr 5631  df-we 5633  df-xp 5682  df-rel 5683  df-cnv 5684  df-co 5685  df-dm 5686  df-rn 5687  df-res 5688  df-ima 5689  df-ord 6367  df-on 6368  df-lim 6369  df-suc 6370  df-iota 6495  df-fun 6545  df-fn 6546  df-f 6547  df-f1 6548  df-fo 6549  df-f1o 6550  df-fv 6551  df-om 7860  df-1o 8472  df-en 8946  df-fin 8949
This theorem is referenced by:  php  9216  onomeneqOLD  9235  nnsdomo  9240  fineqvlem  9268  dif1ennnALT  9283  findcard2OLD  9290  cardnn  9964  satfun  34867
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