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Theorem f1iun 7937
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 3467 . . . . . . . . . 10 𝑢 ∈ V
2 eqeq1 2773 . . . . . . . . . . 11 (𝑧 = 𝑢 → (𝑧 = 𝐵𝑢 = 𝐵))
32rexbidv 3195 . . . . . . . . . 10 (𝑧 = 𝑢 → (∃𝑥𝐴 𝑧 = 𝐵 ↔ ∃𝑥𝐴 𝑢 = 𝐵))
41, 3elab 3647 . . . . . . . . 9 (𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ↔ ∃𝑥𝐴 𝑢 = 𝐵)
5 r19.29 3134 . . . . . . . . . 10 ((∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ ∃𝑥𝐴 𝑢 = 𝐵) → ∃𝑥𝐴 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵))
6 nfv 1941 . . . . . . . . . . . 12 𝑥(Fun 𝑢 ∧ Fun 𝑢)
7 nfre1 3296 . . . . . . . . . . . . . 14 𝑥𝑥𝐴 𝑧 = 𝐵
87nfab 2937 . . . . . . . . . . . . 13 𝑥{𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}
9 nfv 1941 . . . . . . . . . . . . 13 𝑥(𝑢𝑣𝑣𝑢)
108, 9nfralw 3318 . . . . . . . . . . . 12 𝑥𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)
116, 10nfan 1926 . . . . . . . . . . 11 𝑥((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))
12 f1eq1 6767 . . . . . . . . . . . . . . . 16 (𝑢 = 𝐵 → (𝑢:𝐷1-1𝑆𝐵:𝐷1-1𝑆))
1312biimparc 484 . . . . . . . . . . . . . . 15 ((𝐵:𝐷1-1𝑆𝑢 = 𝐵) → 𝑢:𝐷1-1𝑆)
14 df-f1 6539 . . . . . . . . . . . . . . . 16 (𝑢:𝐷1-1𝑆 ↔ (𝑢:𝐷𝑆 ∧ Fun 𝑢))
15 ffun 6706 . . . . . . . . . . . . . . . . 17 (𝑢:𝐷𝑆 → Fun 𝑢)
1615anim1i 626 . . . . . . . . . . . . . . . 16 ((𝑢:𝐷𝑆 ∧ Fun 𝑢) → (Fun 𝑢 ∧ Fun 𝑢))
1714, 16sylbi 220 . . . . . . . . . . . . . . 15 (𝑢:𝐷1-1𝑆 → (Fun 𝑢 ∧ Fun 𝑢))
1813, 17syl 18 . . . . . . . . . . . . . 14 ((𝐵:𝐷1-1𝑆𝑢 = 𝐵) → (Fun 𝑢 ∧ Fun 𝑢))
1918adantlr 727 . . . . . . . . . . . . 13 (((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → (Fun 𝑢 ∧ Fun 𝑢))
20 f1f 6772 . . . . . . . . . . . . . 14 (𝐵:𝐷1-1𝑆𝐵:𝐷𝑆)
21 fiun.1 . . . . . . . . . . . . . . 15 (𝑥 = 𝑦𝐵 = 𝐶)
2221fiunlem 7935 . . . . . . . . . . . . . 14 (((𝐵:𝐷𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))
2320, 22sylanl1 692 . . . . . . . . . . . . 13 (((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))
2419, 23jca 520 . . . . . . . . . . . 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 3271 . . . . . . . . . 10 (∃𝑥𝐴 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
275, 26syl 18 . . . . . . . . 9 ((∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ ∃𝑥𝐴 𝑢 = 𝐵) → ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
284, 27sylan2b 605 . . . . . . . 8 ((∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}) → ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
2928ralrimiva 3163 . . . . . . 7 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ∀𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
30 fun11uni 7926 . . . . . . 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 18 . . . . . 6 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ∧ Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}))
3231simpld 499 . . . . 5 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
33 fiun.2 . . . . . . 7 𝐵 ∈ V
3433dfiun2 4997 . . . . . 6 𝑥𝐴 𝐵 = {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}
3534funeqi 6555 . . . . 5 (Fun 𝑥𝐴 𝐵 ↔ Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
3632, 35sylibr 237 . . . 4 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun 𝑥𝐴 𝐵)
371eldm2 5889 . . . . . . . . 9 (𝑢 ∈ dom 𝐵 ↔ ∃𝑣𝑢, 𝑣⟩ ∈ 𝐵)
38 f1dm 6778 . . . . . . . . . 10 (𝐵:𝐷1-1𝑆 → dom 𝐵 = 𝐷)
3938eleq2d 2855 . . . . . . . . 9 (𝐵:𝐷1-1𝑆 → (𝑢 ∈ dom 𝐵𝑢𝐷))
4037, 39bitr3id 288 . . . . . . . 8 (𝐵:𝐷1-1𝑆 → (∃𝑣𝑢, 𝑣⟩ ∈ 𝐵𝑢𝐷))
4140adantr 485 . . . . . . 7 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (∃𝑣𝑢, 𝑣⟩ ∈ 𝐵𝑢𝐷))
4241ralrexbid 3128 . . . . . 6 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (∃𝑥𝐴𝑣𝑢, 𝑣⟩ ∈ 𝐵 ↔ ∃𝑥𝐴 𝑢𝐷))
43 eliun 4961 . . . . . . . 8 (⟨𝑢, 𝑣⟩ ∈ 𝑥𝐴 𝐵 ↔ ∃𝑥𝐴𝑢, 𝑣⟩ ∈ 𝐵)
4443exbii 1875 . . . . . . 7 (∃𝑣𝑢, 𝑣⟩ ∈ 𝑥𝐴 𝐵 ↔ ∃𝑣𝑥𝐴𝑢, 𝑣⟩ ∈ 𝐵)
451eldm2 5889 . . . . . . 7 (𝑢 ∈ dom 𝑥𝐴 𝐵 ↔ ∃𝑣𝑢, 𝑣⟩ ∈ 𝑥𝐴 𝐵)
46 rexcom4 3298 . . . . . . 7 (∃𝑥𝐴𝑣𝑢, 𝑣⟩ ∈ 𝐵 ↔ ∃𝑣𝑥𝐴𝑢, 𝑣⟩ ∈ 𝐵)
4744, 45, 463bitr4i 306 . . . . . 6 (𝑢 ∈ dom 𝑥𝐴 𝐵 ↔ ∃𝑥𝐴𝑣𝑢, 𝑣⟩ ∈ 𝐵)
48 eliun 4961 . . . . . 6 (𝑢 𝑥𝐴 𝐷 ↔ ∃𝑥𝐴 𝑢𝐷)
4942, 47, 483bitr4g 317 . . . . 5 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (𝑢 ∈ dom 𝑥𝐴 𝐵𝑢 𝑥𝐴 𝐷))
5049eqrdv 2767 . . . 4 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → dom 𝑥𝐴 𝐵 = 𝑥𝐴 𝐷)
51 df-fn 6537 . . . 4 ( 𝑥𝐴 𝐵 Fn 𝑥𝐴 𝐷 ↔ (Fun 𝑥𝐴 𝐵 ∧ dom 𝑥𝐴 𝐵 = 𝑥𝐴 𝐷))
5236, 50, 51sylanbrc 594 . . 3 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵 Fn 𝑥𝐴 𝐷)
53 rniun 6143 . . . 4 ran 𝑥𝐴 𝐵 = 𝑥𝐴 ran 𝐵
5420frnd 6712 . . . . . . 7 (𝐵:𝐷1-1𝑆 → ran 𝐵𝑆)
5554adantr 485 . . . . . 6 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ran 𝐵𝑆)
5655ralimi 3108 . . . . 5 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ∀𝑥𝐴 ran 𝐵𝑆)
57 iunss 5010 . . . . 5 ( 𝑥𝐴 ran 𝐵𝑆 ↔ ∀𝑥𝐴 ran 𝐵𝑆)
5856, 57sylibr 237 . . . 4 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 ran 𝐵𝑆)
5953, 58eqsstrid 3983 . . 3 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ran 𝑥𝐴 𝐵𝑆)
60 df-f 6538 . . 3 ( 𝑥𝐴 𝐵: 𝑥𝐴 𝐷𝑆 ↔ ( 𝑥𝐴 𝐵 Fn 𝑥𝐴 𝐷 ∧ ran 𝑥𝐴 𝐵𝑆))
6152, 59, 60sylanbrc 594 . 2 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵: 𝑥𝐴 𝐷𝑆)
6231simprd 500 . . 3 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
6334cnveqi 5858 . . . 4 𝑥𝐴 𝐵 = {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}
6463funeqi 6555 . . 3 (Fun 𝑥𝐴 𝐵 ↔ Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
6562, 64sylibr 237 . 2 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun 𝑥𝐴 𝐵)
66 df-f1 6539 . 2 ( 𝑥𝐴 𝐵: 𝑥𝐴 𝐷1-1𝑆 ↔ ( 𝑥𝐴 𝐵: 𝑥𝐴 𝐷𝑆 ∧ Fun 𝑥𝐴 𝐵))
6761, 65, 66sylanbrc 594 1 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵: 𝑥𝐴 𝐷1-1𝑆)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 209  wa 400  wo 860   = wceq 1567  wex 1806  wcel 2149  {cab 2747  wral 3085  wrex 3095  Vcvv 3463  wss 3913  cop 4597   cuni 4873   ciun 4957  ccnv 5658  dom cdm 5659  ran crn 5660  Fun wfun 6528   Fn wfn 6529  wf 6530  1-1wf1 6531
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1822  ax-4 1836  ax-5 1937  ax-6 1994  ax-7 2035  ax-8 2151  ax-9 2159  ax-10 2182  ax-11 2198  ax-12 2219  ax-ext 2741  ax-sep 5258  ax-pow 5334  ax-pr 5402  ax-un 7730
This theorem depends on definitions:  df-bi 210  df-an 401  df-or 861  df-3an 1103  df-tru 1570  df-fal 1580  df-ex 1807  df-nf 1811  df-sb 2098  df-clab 2748  df-cleq 2761  df-clel 2844  df-nfc 2918  df-ral 3086  df-rex 3096  df-rab 3424  df-v 3465  df-dif 3916  df-un 3918  df-in 3920  df-ss 3930  df-nul 4295  df-if 4490  df-pw 4566  df-sn 4592  df-pr 4594  df-op 4598  df-uni 4874  df-iun 4959  df-br 5111  df-opab 5175  df-id 5554  df-xp 5665  df-rel 5666  df-cnv 5667  df-co 5668  df-dm 5669  df-rn 5670  df-fun 6536  df-fn 6537  df-f 6538  df-f1 6539
This theorem is referenced by:  ackbij2  10221
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