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Theorem carduni 9963
Description: The union of a set of cardinals is a cardinal. Theorem 18.14 of [Monk1] p. 133. (Contributed by Mario Carneiro, 20-Jan-2013.)
Assertion
Ref Expression
carduni (𝐴𝑉 → (∀𝑥𝐴 (card‘𝑥) = 𝑥 → (card‘ 𝐴) = 𝐴))
Distinct variable group:   𝑥,𝐴
Allowed substitution hint:   𝑉(𝑥)

Proof of Theorem carduni
Dummy variable 𝑦 is distinct from all other variables.
StepHypRef Expression
1 ssonuni 7754 . . . . 5 (𝐴𝑉 → (𝐴 ⊆ On → 𝐴 ∈ On))
2 fveq2 6881 . . . . . . . . 9 (𝑥 = 𝑦 → (card‘𝑥) = (card‘𝑦))
3 id 22 . . . . . . . . 9 (𝑥 = 𝑦𝑥 = 𝑦)
42, 3eqeq12d 2749 . . . . . . . 8 (𝑥 = 𝑦 → ((card‘𝑥) = 𝑥 ↔ (card‘𝑦) = 𝑦))
54rspcv 3607 . . . . . . 7 (𝑦𝐴 → (∀𝑥𝐴 (card‘𝑥) = 𝑥 → (card‘𝑦) = 𝑦))
6 cardon 9926 . . . . . . . 8 (card‘𝑦) ∈ On
7 eleq1 2822 . . . . . . . 8 ((card‘𝑦) = 𝑦 → ((card‘𝑦) ∈ On ↔ 𝑦 ∈ On))
86, 7mpbii 232 . . . . . . 7 ((card‘𝑦) = 𝑦𝑦 ∈ On)
95, 8syl6com 37 . . . . . 6 (∀𝑥𝐴 (card‘𝑥) = 𝑥 → (𝑦𝐴𝑦 ∈ On))
109ssrdv 3986 . . . . 5 (∀𝑥𝐴 (card‘𝑥) = 𝑥𝐴 ⊆ On)
111, 10impel 507 . . . 4 ((𝐴𝑉 ∧ ∀𝑥𝐴 (card‘𝑥) = 𝑥) → 𝐴 ∈ On)
12 cardonle 9939 . . . 4 ( 𝐴 ∈ On → (card‘ 𝐴) ⊆ 𝐴)
1311, 12syl 17 . . 3 ((𝐴𝑉 ∧ ∀𝑥𝐴 (card‘𝑥) = 𝑥) → (card‘ 𝐴) ⊆ 𝐴)
14 cardon 9926 . . . . 5 (card‘ 𝐴) ∈ On
1514onirri 6469 . . . 4 ¬ (card‘ 𝐴) ∈ (card‘ 𝐴)
16 eluni 4907 . . . . . . . 8 ((card‘ 𝐴) ∈ 𝐴 ↔ ∃𝑦((card‘ 𝐴) ∈ 𝑦𝑦𝐴))
17 elssuni 4937 . . . . . . . . . . . . . . . . . 18 (𝑦𝐴𝑦 𝐴)
18 ssdomg 8984 . . . . . . . . . . . . . . . . . . 19 ( 𝐴 ∈ On → (𝑦 𝐴𝑦 𝐴))
1918adantl 483 . . . . . . . . . . . . . . . . . 18 (((card‘𝑦) = 𝑦 𝐴 ∈ On) → (𝑦 𝐴𝑦 𝐴))
2017, 19syl5 34 . . . . . . . . . . . . . . . . 17 (((card‘𝑦) = 𝑦 𝐴 ∈ On) → (𝑦𝐴𝑦 𝐴))
21 id 22 . . . . . . . . . . . . . . . . . . 19 ((card‘𝑦) = 𝑦 → (card‘𝑦) = 𝑦)
22 onenon 9931 . . . . . . . . . . . . . . . . . . . 20 ((card‘𝑦) ∈ On → (card‘𝑦) ∈ dom card)
236, 22ax-mp 5 . . . . . . . . . . . . . . . . . . 19 (card‘𝑦) ∈ dom card
2421, 23eqeltrrdi 2843 . . . . . . . . . . . . . . . . . 18 ((card‘𝑦) = 𝑦𝑦 ∈ dom card)
25 onenon 9931 . . . . . . . . . . . . . . . . . 18 ( 𝐴 ∈ On → 𝐴 ∈ dom card)
26 carddom2 9959 . . . . . . . . . . . . . . . . . 18 ((𝑦 ∈ dom card ∧ 𝐴 ∈ dom card) → ((card‘𝑦) ⊆ (card‘ 𝐴) ↔ 𝑦 𝐴))
2724, 25, 26syl2an 597 . . . . . . . . . . . . . . . . 17 (((card‘𝑦) = 𝑦 𝐴 ∈ On) → ((card‘𝑦) ⊆ (card‘ 𝐴) ↔ 𝑦 𝐴))
2820, 27sylibrd 259 . . . . . . . . . . . . . . . 16 (((card‘𝑦) = 𝑦 𝐴 ∈ On) → (𝑦𝐴 → (card‘𝑦) ⊆ (card‘ 𝐴)))
29 sseq1 4005 . . . . . . . . . . . . . . . . 17 ((card‘𝑦) = 𝑦 → ((card‘𝑦) ⊆ (card‘ 𝐴) ↔ 𝑦 ⊆ (card‘ 𝐴)))
3029adantr 482 . . . . . . . . . . . . . . . 16 (((card‘𝑦) = 𝑦 𝐴 ∈ On) → ((card‘𝑦) ⊆ (card‘ 𝐴) ↔ 𝑦 ⊆ (card‘ 𝐴)))
3128, 30sylibd 238 . . . . . . . . . . . . . . 15 (((card‘𝑦) = 𝑦 𝐴 ∈ On) → (𝑦𝐴𝑦 ⊆ (card‘ 𝐴)))
32 ssel 3973 . . . . . . . . . . . . . . 15 (𝑦 ⊆ (card‘ 𝐴) → ((card‘ 𝐴) ∈ 𝑦 → (card‘ 𝐴) ∈ (card‘ 𝐴)))
3331, 32syl6 35 . . . . . . . . . . . . . 14 (((card‘𝑦) = 𝑦 𝐴 ∈ On) → (𝑦𝐴 → ((card‘ 𝐴) ∈ 𝑦 → (card‘ 𝐴) ∈ (card‘ 𝐴))))
3433ex 414 . . . . . . . . . . . . 13 ((card‘𝑦) = 𝑦 → ( 𝐴 ∈ On → (𝑦𝐴 → ((card‘ 𝐴) ∈ 𝑦 → (card‘ 𝐴) ∈ (card‘ 𝐴)))))
3534com3r 87 . . . . . . . . . . . 12 (𝑦𝐴 → ((card‘𝑦) = 𝑦 → ( 𝐴 ∈ On → ((card‘ 𝐴) ∈ 𝑦 → (card‘ 𝐴) ∈ (card‘ 𝐴)))))
365, 35syld 47 . . . . . . . . . . 11 (𝑦𝐴 → (∀𝑥𝐴 (card‘𝑥) = 𝑥 → ( 𝐴 ∈ On → ((card‘ 𝐴) ∈ 𝑦 → (card‘ 𝐴) ∈ (card‘ 𝐴)))))
3736com4r 94 . . . . . . . . . 10 ((card‘ 𝐴) ∈ 𝑦 → (𝑦𝐴 → (∀𝑥𝐴 (card‘𝑥) = 𝑥 → ( 𝐴 ∈ On → (card‘ 𝐴) ∈ (card‘ 𝐴)))))
3837imp 408 . . . . . . . . 9 (((card‘ 𝐴) ∈ 𝑦𝑦𝐴) → (∀𝑥𝐴 (card‘𝑥) = 𝑥 → ( 𝐴 ∈ On → (card‘ 𝐴) ∈ (card‘ 𝐴))))
3938exlimiv 1934 . . . . . . . 8 (∃𝑦((card‘ 𝐴) ∈ 𝑦𝑦𝐴) → (∀𝑥𝐴 (card‘𝑥) = 𝑥 → ( 𝐴 ∈ On → (card‘ 𝐴) ∈ (card‘ 𝐴))))
4016, 39sylbi 216 . . . . . . 7 ((card‘ 𝐴) ∈ 𝐴 → (∀𝑥𝐴 (card‘𝑥) = 𝑥 → ( 𝐴 ∈ On → (card‘ 𝐴) ∈ (card‘ 𝐴))))
4140com13 88 . . . . . 6 ( 𝐴 ∈ On → (∀𝑥𝐴 (card‘𝑥) = 𝑥 → ((card‘ 𝐴) ∈ 𝐴 → (card‘ 𝐴) ∈ (card‘ 𝐴))))
4241imp 408 . . . . 5 (( 𝐴 ∈ On ∧ ∀𝑥𝐴 (card‘𝑥) = 𝑥) → ((card‘ 𝐴) ∈ 𝐴 → (card‘ 𝐴) ∈ (card‘ 𝐴)))
4311, 42sylancom 589 . . . 4 ((𝐴𝑉 ∧ ∀𝑥𝐴 (card‘𝑥) = 𝑥) → ((card‘ 𝐴) ∈ 𝐴 → (card‘ 𝐴) ∈ (card‘ 𝐴)))
4415, 43mtoi 198 . . 3 ((𝐴𝑉 ∧ ∀𝑥𝐴 (card‘𝑥) = 𝑥) → ¬ (card‘ 𝐴) ∈ 𝐴)
4514onordi 6467 . . . 4 Ord (card‘ 𝐴)
46 eloni 6366 . . . . 5 ( 𝐴 ∈ On → Ord 𝐴)
4711, 46syl 17 . . . 4 ((𝐴𝑉 ∧ ∀𝑥𝐴 (card‘𝑥) = 𝑥) → Ord 𝐴)
48 ordtri4 6393 . . . 4 ((Ord (card‘ 𝐴) ∧ Ord 𝐴) → ((card‘ 𝐴) = 𝐴 ↔ ((card‘ 𝐴) ⊆ 𝐴 ∧ ¬ (card‘ 𝐴) ∈ 𝐴)))
4945, 47, 48sylancr 588 . . 3 ((𝐴𝑉 ∧ ∀𝑥𝐴 (card‘𝑥) = 𝑥) → ((card‘ 𝐴) = 𝐴 ↔ ((card‘ 𝐴) ⊆ 𝐴 ∧ ¬ (card‘ 𝐴) ∈ 𝐴)))
5013, 44, 49mpbir2and 712 . 2 ((𝐴𝑉 ∧ ∀𝑥𝐴 (card‘𝑥) = 𝑥) → (card‘ 𝐴) = 𝐴)
5150ex 414 1 (𝐴𝑉 → (∀𝑥𝐴 (card‘𝑥) = 𝑥 → (card‘ 𝐴) = 𝐴))
Colors of variables: wff setvar class
Syntax hints:  ¬ wn 3  wi 4  wb 205  wa 397   = wceq 1542  wex 1782  wcel 2107  wral 3062  wss 3946   cuni 4904   class class class wbr 5144  dom cdm 5672  Ord word 6355  Oncon0 6356  cfv 6535  cdom 8925  cardccrd 9917
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-10 2138  ax-11 2155  ax-12 2172  ax-ext 2704  ax-sep 5295  ax-nul 5302  ax-pow 5359  ax-pr 5423  ax-un 7712
This theorem depends on definitions:  df-bi 206  df-an 398  df-or 847  df-3or 1089  df-3an 1090  df-tru 1545  df-fal 1555  df-ex 1783  df-nf 1787  df-sb 2069  df-mo 2535  df-eu 2564  df-clab 2711  df-cleq 2725  df-clel 2811  df-nfc 2886  df-ne 2942  df-ral 3063  df-rex 3072  df-rab 3434  df-v 3477  df-dif 3949  df-un 3951  df-in 3953  df-ss 3963  df-pss 3965  df-nul 4321  df-if 4525  df-pw 4600  df-sn 4625  df-pr 4627  df-op 4631  df-uni 4905  df-int 4947  df-br 5145  df-opab 5207  df-mpt 5228  df-tr 5262  df-id 5570  df-eprel 5576  df-po 5584  df-so 5585  df-fr 5627  df-we 5629  df-xp 5678  df-rel 5679  df-cnv 5680  df-co 5681  df-dm 5682  df-rn 5683  df-res 5684  df-ima 5685  df-ord 6359  df-on 6360  df-iota 6487  df-fun 6537  df-fn 6538  df-f 6539  df-f1 6540  df-fo 6541  df-f1o 6542  df-fv 6543  df-er 8691  df-en 8928  df-dom 8929  df-sdom 8930  df-card 9921
This theorem is referenced by:  cardiun  9964  carduniima  10078
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