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Theorem f1iun 7886
Description: The union of a chain (with respect to inclusion) of one-to-one functions is a one-to-one function. (Contributed by Mario Carneiro, 20-May-2013.) (Revised by Mario Carneiro, 24-Jun-2015.) (Proof shortened by AV, 5-Nov-2023.)
Hypotheses
Ref Expression
fiun.1 (𝑥 = 𝑦𝐵 = 𝐶)
fiun.2 𝐵 ∈ V
Assertion
Ref Expression
f1iun (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵: 𝑥𝐴 𝐷1-1𝑆)
Distinct variable groups:   𝑥,𝐴,𝑦   𝑦,𝐵   𝑥,𝐶   𝑥,𝑦   𝑥,𝑆
Allowed substitution hints:   𝐵(𝑥)   𝐶(𝑦)   𝐷(𝑥,𝑦)   𝑆(𝑦)

Proof of Theorem f1iun
Dummy variables 𝑣 𝑧 𝑢 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 vex 3435 . . . . . . . . . 10 𝑢 ∈ V
2 eqeq1 2743 . . . . . . . . . . 11 (𝑧 = 𝑢 → (𝑧 = 𝐵𝑢 = 𝐵))
32rexbidv 3163 . . . . . . . . . 10 (𝑧 = 𝑢 → (∃𝑥𝐴 𝑧 = 𝐵 ↔ ∃𝑥𝐴 𝑢 = 𝐵))
41, 3elab 3617 . . . . . . . . 9 (𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ↔ ∃𝑥𝐴 𝑢 = 𝐵)
5 r19.29 3102 . . . . . . . . . 10 ((∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ ∃𝑥𝐴 𝑢 = 𝐵) → ∃𝑥𝐴 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵))
6 nfv 1921 . . . . . . . . . . . 12 𝑥(Fun 𝑢 ∧ Fun 𝑢)
7 nfre1 3264 . . . . . . . . . . . . . 14 𝑥𝑥𝐴 𝑧 = 𝐵
87nfab 2907 . . . . . . . . . . . . 13 𝑥{𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}
9 nfv 1921 . . . . . . . . . . . . 13 𝑥(𝑢𝑣𝑣𝑢)
108, 9nfralw 3286 . . . . . . . . . . . 12 𝑥𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)
116, 10nfan 1906 . . . . . . . . . . 11 𝑥((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))
12 f1eq1 6718 . . . . . . . . . . . . . . . 16 (𝑢 = 𝐵 → (𝑢:𝐷1-1𝑆𝐵:𝐷1-1𝑆))
1312biimparc 480 . . . . . . . . . . . . . . 15 ((𝐵:𝐷1-1𝑆𝑢 = 𝐵) → 𝑢:𝐷1-1𝑆)
14 df-f1 6490 . . . . . . . . . . . . . . . 16 (𝑢:𝐷1-1𝑆 ↔ (𝑢:𝐷𝑆 ∧ Fun 𝑢))
15 ffun 6658 . . . . . . . . . . . . . . . . 17 (𝑢:𝐷𝑆 → Fun 𝑢)
1615anim1i 621 . . . . . . . . . . . . . . . 16 ((𝑢:𝐷𝑆 ∧ Fun 𝑢) → (Fun 𝑢 ∧ Fun 𝑢))
1714, 16sylbi 218 . . . . . . . . . . . . . . 15 (𝑢:𝐷1-1𝑆 → (Fun 𝑢 ∧ Fun 𝑢))
1813, 17syl 17 . . . . . . . . . . . . . 14 ((𝐵:𝐷1-1𝑆𝑢 = 𝐵) → (Fun 𝑢 ∧ Fun 𝑢))
1918adantlr 721 . . . . . . . . . . . . 13 (((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → (Fun 𝑢 ∧ Fun 𝑢))
20 f1f 6723 . . . . . . . . . . . . . 14 (𝐵:𝐷1-1𝑆𝐵:𝐷𝑆)
21 fiun.1 . . . . . . . . . . . . . . 15 (𝑥 = 𝑦𝐵 = 𝐶)
2221fiunlem 7884 . . . . . . . . . . . . . 14 (((𝐵:𝐷𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))
2320, 22sylanl1 686 . . . . . . . . . . . . 13 (((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))
2419, 23jca 516 . . . . . . . . . . . 12 (((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
2524a1i 11 . . . . . . . . . . 11 (𝑥𝐴 → (((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))))
2611, 25rexlimi 3239 . . . . . . . . . 10 (∃𝑥𝐴 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
275, 26syl 17 . . . . . . . . 9 ((∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ ∃𝑥𝐴 𝑢 = 𝐵) → ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
284, 27sylan2b 600 . . . . . . . 8 ((∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}) → ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
2928ralrimiva 3131 . . . . . . 7 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ∀𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
30 fun11uni 7873 . . . . . . 7 (∀𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)) → (Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ∧ Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}))
3129, 30syl 17 . . . . . 6 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ∧ Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}))
3231simpld 495 . . . . 5 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
33 fiun.2 . . . . . . 7 𝐵 ∈ V
3433dfiun2 4961 . . . . . 6 𝑥𝐴 𝐵 = {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}
3534funeqi 6506 . . . . 5 (Fun 𝑥𝐴 𝐵 ↔ Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
3632, 35sylibr 235 . . . 4 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun 𝑥𝐴 𝐵)
371eldm2 5843 . . . . . . . . 9 (𝑢 ∈ dom 𝐵 ↔ ∃𝑣𝑢, 𝑣⟩ ∈ 𝐵)
38 f1dm 6727 . . . . . . . . . 10 (𝐵:𝐷1-1𝑆 → dom 𝐵 = 𝐷)
3938eleq2d 2825 . . . . . . . . 9 (𝐵:𝐷1-1𝑆 → (𝑢 ∈ dom 𝐵𝑢𝐷))
4037, 39bitr3id 286 . . . . . . . 8 (𝐵:𝐷1-1𝑆 → (∃𝑣𝑢, 𝑣⟩ ∈ 𝐵𝑢𝐷))
4140adantr 481 . . . . . . 7 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (∃𝑣𝑢, 𝑣⟩ ∈ 𝐵𝑢𝐷))
4241ralrexbid 3096 . . . . . 6 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (∃𝑥𝐴𝑣𝑢, 𝑣⟩ ∈ 𝐵 ↔ ∃𝑥𝐴 𝑢𝐷))
43 eliun 4925 . . . . . . . 8 (⟨𝑢, 𝑣⟩ ∈ 𝑥𝐴 𝐵 ↔ ∃𝑥𝐴𝑢, 𝑣⟩ ∈ 𝐵)
4443exbii 1855 . . . . . . 7 (∃𝑣𝑢, 𝑣⟩ ∈ 𝑥𝐴 𝐵 ↔ ∃𝑣𝑥𝐴𝑢, 𝑣⟩ ∈ 𝐵)
451eldm2 5843 . . . . . . 7 (𝑢 ∈ dom 𝑥𝐴 𝐵 ↔ ∃𝑣𝑢, 𝑣⟩ ∈ 𝑥𝐴 𝐵)
46 rexcom4 3266 . . . . . . 7 (∃𝑥𝐴𝑣𝑢, 𝑣⟩ ∈ 𝐵 ↔ ∃𝑣𝑥𝐴𝑢, 𝑣⟩ ∈ 𝐵)
4744, 45, 463bitr4i 304 . . . . . 6 (𝑢 ∈ dom 𝑥𝐴 𝐵 ↔ ∃𝑥𝐴𝑣𝑢, 𝑣⟩ ∈ 𝐵)
48 eliun 4925 . . . . . 6 (𝑢 𝑥𝐴 𝐷 ↔ ∃𝑥𝐴 𝑢𝐷)
4942, 47, 483bitr4g 315 . . . . 5 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (𝑢 ∈ dom 𝑥𝐴 𝐵𝑢 𝑥𝐴 𝐷))
5049eqrdv 2737 . . . 4 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → dom 𝑥𝐴 𝐵 = 𝑥𝐴 𝐷)
51 df-fn 6488 . . . 4 ( 𝑥𝐴 𝐵 Fn 𝑥𝐴 𝐷 ↔ (Fun 𝑥𝐴 𝐵 ∧ dom 𝑥𝐴 𝐵 = 𝑥𝐴 𝐷))
5236, 50, 51sylanbrc 589 . . 3 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵 Fn 𝑥𝐴 𝐷)
53 rniun 6098 . . . 4 ran 𝑥𝐴 𝐵 = 𝑥𝐴 ran 𝐵
5420frnd 6663 . . . . . . 7 (𝐵:𝐷1-1𝑆 → ran 𝐵𝑆)
5554adantr 481 . . . . . 6 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ran 𝐵𝑆)
5655ralimi 3076 . . . . 5 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ∀𝑥𝐴 ran 𝐵𝑆)
57 iunss 4974 . . . . 5 ( 𝑥𝐴 ran 𝐵𝑆 ↔ ∀𝑥𝐴 ran 𝐵𝑆)
5856, 57sylibr 235 . . . 4 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 ran 𝐵𝑆)
5953, 58eqsstrid 3953 . . 3 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ran 𝑥𝐴 𝐵𝑆)
60 df-f 6489 . . 3 ( 𝑥𝐴 𝐵: 𝑥𝐴 𝐷𝑆 ↔ ( 𝑥𝐴 𝐵 Fn 𝑥𝐴 𝐷 ∧ ran 𝑥𝐴 𝐵𝑆))
6152, 59, 60sylanbrc 589 . 2 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵: 𝑥𝐴 𝐷𝑆)
6231simprd 496 . . 3 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
6334cnveqi 5816 . . . 4 𝑥𝐴 𝐵 = {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}
6463funeqi 6506 . . 3 (Fun 𝑥𝐴 𝐵 ↔ Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
6562, 64sylibr 235 . 2 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun 𝑥𝐴 𝐵)
66 df-f1 6490 . 2 ( 𝑥𝐴 𝐵: 𝑥𝐴 𝐷1-1𝑆 ↔ ( 𝑥𝐴 𝐵: 𝑥𝐴 𝐷𝑆 ∧ Fun 𝑥𝐴 𝐵))
6761, 65, 66sylanbrc 589 1 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵: 𝑥𝐴 𝐷1-1𝑆)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 207  wa 396  wo 853   = wceq 1547  wex 1786  wcel 2119  {cab 2717  wral 3053  wrex 3063  Vcvv 3431  wss 3883  cop 4561   cuni 4838   ciun 4921  ccnv 5617  dom cdm 5618  ran crn 5619  Fun wfun 6479   Fn wfn 6480  wf 6481  1-1wf1 6482
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1917  ax-6 1974  ax-7 2015  ax-8 2121  ax-9 2129  ax-10 2152  ax-11 2168  ax-12 2189  ax-ext 2711  ax-sep 5218  ax-pow 5294  ax-pr 5362  ax-un 7678
This theorem depends on definitions:  df-bi 208  df-an 397  df-or 854  df-3an 1094  df-tru 1550  df-fal 1560  df-ex 1787  df-nf 1791  df-sb 2074  df-clab 2718  df-cleq 2731  df-clel 2814  df-nfc 2888  df-ral 3054  df-rex 3064  df-rab 3392  df-v 3433  df-dif 3886  df-un 3888  df-in 3890  df-ss 3900  df-nul 4262  df-if 4455  df-pw 4531  df-sn 4556  df-pr 4558  df-op 4562  df-uni 4839  df-iun 4923  df-br 5073  df-opab 5135  df-id 5513  df-xp 5624  df-rel 5625  df-cnv 5626  df-co 5627  df-dm 5628  df-rn 5629  df-fun 6487  df-fn 6488  df-f 6489  df-f1 6490
This theorem is referenced by:  ackbij2  10155
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