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Theorem cardf2 9981
Description: The cardinality function is a function with domain the well-orderable sets. Assuming AC, this is the universe. (Contributed by Mario Carneiro, 6-Jun-2013.) (Revised by Mario Carneiro, 20-Sep-2014.)
Assertion
Ref Expression
cardf2 card:{𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥}⟶On
Distinct variable group:   𝑥,𝑦

Proof of Theorem cardf2
Dummy variables 𝑤 𝑧 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 df-card 9977 . . . 4 card = (𝑥 ∈ V ↦ {𝑦 ∈ On ∣ 𝑦𝑥})
21funmpt2 6607 . . 3 Fun card
3 rabab 3510 . . . 4 {𝑥 ∈ V ∣ {𝑦 ∈ On ∣ 𝑦𝑥} ∈ V} = {𝑥 {𝑦 ∈ On ∣ 𝑦𝑥} ∈ V}
41dmmpt 6262 . . . 4 dom card = {𝑥 ∈ V ∣ {𝑦 ∈ On ∣ 𝑦𝑥} ∈ V}
5 intexrab 5353 . . . . 5 (∃𝑦 ∈ On 𝑦𝑥 {𝑦 ∈ On ∣ 𝑦𝑥} ∈ V)
65abbii 2807 . . . 4 {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} = {𝑥 {𝑦 ∈ On ∣ 𝑦𝑥} ∈ V}
73, 4, 63eqtr4i 2773 . . 3 dom card = {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥}
8 df-fn 6566 . . 3 (card Fn {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} ↔ (Fun card ∧ dom card = {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥}))
92, 7, 8mpbir2an 711 . 2 card Fn {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥}
10 simpr 484 . . . . . . . . 9 ((𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧}) → 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧})
11 vex 3482 . . . . . . . . 9 𝑤 ∈ V
1210, 11eqeltrrdi 2848 . . . . . . . 8 ((𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧}) → {𝑦 ∈ On ∣ 𝑦𝑧} ∈ V)
13 intex 5350 . . . . . . . 8 ({𝑦 ∈ On ∣ 𝑦𝑧} ≠ ∅ ↔ {𝑦 ∈ On ∣ 𝑦𝑧} ∈ V)
1412, 13sylibr 234 . . . . . . 7 ((𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧}) → {𝑦 ∈ On ∣ 𝑦𝑧} ≠ ∅)
15 rabn0 4395 . . . . . . 7 ({𝑦 ∈ On ∣ 𝑦𝑧} ≠ ∅ ↔ ∃𝑦 ∈ On 𝑦𝑧)
1614, 15sylib 218 . . . . . 6 ((𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧}) → ∃𝑦 ∈ On 𝑦𝑧)
17 vex 3482 . . . . . . 7 𝑧 ∈ V
18 breq2 5152 . . . . . . . 8 (𝑥 = 𝑧 → (𝑦𝑥𝑦𝑧))
1918rexbidv 3177 . . . . . . 7 (𝑥 = 𝑧 → (∃𝑦 ∈ On 𝑦𝑥 ↔ ∃𝑦 ∈ On 𝑦𝑧))
2017, 19elab 3681 . . . . . 6 (𝑧 ∈ {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} ↔ ∃𝑦 ∈ On 𝑦𝑧)
2116, 20sylibr 234 . . . . 5 ((𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧}) → 𝑧 ∈ {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥})
22 ssrab2 4090 . . . . . . 7 {𝑦 ∈ On ∣ 𝑦𝑧} ⊆ On
23 oninton 7815 . . . . . . 7 (({𝑦 ∈ On ∣ 𝑦𝑧} ⊆ On ∧ {𝑦 ∈ On ∣ 𝑦𝑧} ≠ ∅) → {𝑦 ∈ On ∣ 𝑦𝑧} ∈ On)
2422, 14, 23sylancr 587 . . . . . 6 ((𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧}) → {𝑦 ∈ On ∣ 𝑦𝑧} ∈ On)
2510, 24eqeltrd 2839 . . . . 5 ((𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧}) → 𝑤 ∈ On)
2621, 25jca 511 . . . 4 ((𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧}) → (𝑧 ∈ {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} ∧ 𝑤 ∈ On))
2726ssopab2i 5560 . . 3 {⟨𝑧, 𝑤⟩ ∣ (𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧})} ⊆ {⟨𝑧, 𝑤⟩ ∣ (𝑧 ∈ {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} ∧ 𝑤 ∈ On)}
28 df-card 9977 . . . 4 card = (𝑧 ∈ V ↦ {𝑦 ∈ On ∣ 𝑦𝑧})
29 df-mpt 5232 . . . 4 (𝑧 ∈ V ↦ {𝑦 ∈ On ∣ 𝑦𝑧}) = {⟨𝑧, 𝑤⟩ ∣ (𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧})}
3028, 29eqtri 2763 . . 3 card = {⟨𝑧, 𝑤⟩ ∣ (𝑧 ∈ V ∧ 𝑤 = {𝑦 ∈ On ∣ 𝑦𝑧})}
31 df-xp 5695 . . 3 ({𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} × On) = {⟨𝑧, 𝑤⟩ ∣ (𝑧 ∈ {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} ∧ 𝑤 ∈ On)}
3227, 30, 313sstr4i 4039 . 2 card ⊆ ({𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} × On)
33 dff2 7119 . 2 (card:{𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥}⟶On ↔ (card Fn {𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} ∧ card ⊆ ({𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥} × On)))
349, 32, 33mpbir2an 711 1 card:{𝑥 ∣ ∃𝑦 ∈ On 𝑦𝑥}⟶On
Colors of variables: wff setvar class
Syntax hints:  wa 395   = wceq 1537  wcel 2106  {cab 2712  wne 2938  wrex 3068  {crab 3433  Vcvv 3478  wss 3963  c0 4339   cint 4951   class class class wbr 5148  {copab 5210  cmpt 5231   × cxp 5687  dom cdm 5689  Oncon0 6386  Fun wfun 6557   Fn wfn 6558  wf 6559  cen 8981  cardccrd 9973
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1908  ax-6 1965  ax-7 2005  ax-8 2108  ax-9 2116  ax-10 2139  ax-11 2155  ax-12 2175  ax-ext 2706  ax-sep 5302  ax-nul 5312  ax-pr 5438
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3or 1087  df-3an 1088  df-tru 1540  df-fal 1550  df-ex 1777  df-nf 1781  df-sb 2063  df-mo 2538  df-eu 2567  df-clab 2713  df-cleq 2727  df-clel 2814  df-nfc 2890  df-ne 2939  df-ral 3060  df-rex 3069  df-rab 3434  df-v 3480  df-dif 3966  df-un 3968  df-in 3970  df-ss 3980  df-pss 3983  df-nul 4340  df-if 4532  df-pw 4607  df-sn 4632  df-pr 4634  df-op 4638  df-uni 4913  df-int 4952  df-br 5149  df-opab 5211  df-mpt 5232  df-tr 5266  df-id 5583  df-eprel 5589  df-po 5597  df-so 5598  df-fr 5641  df-we 5643  df-xp 5695  df-rel 5696  df-cnv 5697  df-co 5698  df-dm 5699  df-rn 5700  df-res 5701  df-ima 5702  df-ord 6389  df-on 6390  df-fun 6565  df-fn 6566  df-f 6567  df-card 9977
This theorem is referenced by:  cardon  9982  isnum2  9983  cardf  10588  smobeth  10624  hashkf  14368  hashgval  14369  cardpred  35083  nummin  35084
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