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Theorem f1iun 7888
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 3444 . . . . . . . . . 10 𝑢 ∈ V
2 eqeq1 2740 . . . . . . . . . . 11 (𝑧 = 𝑢 → (𝑧 = 𝐵𝑢 = 𝐵))
32rexbidv 3160 . . . . . . . . . 10 (𝑧 = 𝑢 → (∃𝑥𝐴 𝑧 = 𝐵 ↔ ∃𝑥𝐴 𝑢 = 𝐵))
41, 3elab 3634 . . . . . . . . 9 (𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ↔ ∃𝑥𝐴 𝑢 = 𝐵)
5 r19.29 3099 . . . . . . . . . 10 ((∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ ∃𝑥𝐴 𝑢 = 𝐵) → ∃𝑥𝐴 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵))
6 nfv 1915 . . . . . . . . . . . 12 𝑥(Fun 𝑢 ∧ Fun 𝑢)
7 nfre1 3261 . . . . . . . . . . . . . 14 𝑥𝑥𝐴 𝑧 = 𝐵
87nfab 2904 . . . . . . . . . . . . 13 𝑥{𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}
9 nfv 1915 . . . . . . . . . . . . 13 𝑥(𝑢𝑣𝑣𝑢)
108, 9nfralw 3283 . . . . . . . . . . . 12 𝑥𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)
116, 10nfan 1900 . . . . . . . . . . 11 𝑥((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))
12 f1eq1 6725 . . . . . . . . . . . . . . . 16 (𝑢 = 𝐵 → (𝑢:𝐷1-1𝑆𝐵:𝐷1-1𝑆))
1312biimparc 479 . . . . . . . . . . . . . . 15 ((𝐵:𝐷1-1𝑆𝑢 = 𝐵) → 𝑢:𝐷1-1𝑆)
14 df-f1 6497 . . . . . . . . . . . . . . . 16 (𝑢:𝐷1-1𝑆 ↔ (𝑢:𝐷𝑆 ∧ Fun 𝑢))
15 ffun 6665 . . . . . . . . . . . . . . . . 17 (𝑢:𝐷𝑆 → Fun 𝑢)
1615anim1i 615 . . . . . . . . . . . . . . . 16 ((𝑢:𝐷𝑆 ∧ Fun 𝑢) → (Fun 𝑢 ∧ Fun 𝑢))
1714, 16sylbi 217 . . . . . . . . . . . . . . 15 (𝑢:𝐷1-1𝑆 → (Fun 𝑢 ∧ Fun 𝑢))
1813, 17syl 17 . . . . . . . . . . . . . 14 ((𝐵:𝐷1-1𝑆𝑢 = 𝐵) → (Fun 𝑢 ∧ Fun 𝑢))
1918adantlr 715 . . . . . . . . . . . . 13 (((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → (Fun 𝑢 ∧ Fun 𝑢))
20 f1f 6730 . . . . . . . . . . . . . 14 (𝐵:𝐷1-1𝑆𝐵:𝐷𝑆)
21 fiun.1 . . . . . . . . . . . . . . 15 (𝑥 = 𝑦𝐵 = 𝐶)
2221fiunlem 7886 . . . . . . . . . . . . . 14 (((𝐵:𝐷𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))
2320, 22sylanl1 680 . . . . . . . . . . . . 13 (((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 = 𝐵) → ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢))
2419, 23jca 511 . . . . . . . . . . . 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 3236 . . . . . . . . . 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 594 . . . . . . . 8 ((∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) ∧ 𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}) → ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
2928ralrimiva 3128 . . . . . . 7 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ∀𝑢 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} ((Fun 𝑢 ∧ Fun 𝑢) ∧ ∀𝑣 ∈ {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵} (𝑢𝑣𝑣𝑢)))
30 fun11uni 7875 . . . . . . 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 494 . . . . 5 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
33 fiun.2 . . . . . . 7 𝐵 ∈ V
3433dfiun2 4987 . . . . . 6 𝑥𝐴 𝐵 = {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}
3534funeqi 6513 . . . . 5 (Fun 𝑥𝐴 𝐵 ↔ Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
3632, 35sylibr 234 . . . 4 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun 𝑥𝐴 𝐵)
371eldm2 5850 . . . . . . . . 9 (𝑢 ∈ dom 𝐵 ↔ ∃𝑣𝑢, 𝑣⟩ ∈ 𝐵)
38 f1dm 6734 . . . . . . . . . 10 (𝐵:𝐷1-1𝑆 → dom 𝐵 = 𝐷)
3938eleq2d 2822 . . . . . . . . 9 (𝐵:𝐷1-1𝑆 → (𝑢 ∈ dom 𝐵𝑢𝐷))
4037, 39bitr3id 285 . . . . . . . 8 (𝐵:𝐷1-1𝑆 → (∃𝑣𝑢, 𝑣⟩ ∈ 𝐵𝑢𝐷))
4140adantr 480 . . . . . . 7 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (∃𝑣𝑢, 𝑣⟩ ∈ 𝐵𝑢𝐷))
4241ralrexbid 3093 . . . . . 6 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (∃𝑥𝐴𝑣𝑢, 𝑣⟩ ∈ 𝐵 ↔ ∃𝑥𝐴 𝑢𝐷))
43 eliun 4950 . . . . . . . 8 (⟨𝑢, 𝑣⟩ ∈ 𝑥𝐴 𝐵 ↔ ∃𝑥𝐴𝑢, 𝑣⟩ ∈ 𝐵)
4443exbii 1849 . . . . . . 7 (∃𝑣𝑢, 𝑣⟩ ∈ 𝑥𝐴 𝐵 ↔ ∃𝑣𝑥𝐴𝑢, 𝑣⟩ ∈ 𝐵)
451eldm2 5850 . . . . . . 7 (𝑢 ∈ dom 𝑥𝐴 𝐵 ↔ ∃𝑣𝑢, 𝑣⟩ ∈ 𝑥𝐴 𝐵)
46 rexcom4 3263 . . . . . . 7 (∃𝑥𝐴𝑣𝑢, 𝑣⟩ ∈ 𝐵 ↔ ∃𝑣𝑥𝐴𝑢, 𝑣⟩ ∈ 𝐵)
4744, 45, 463bitr4i 303 . . . . . 6 (𝑢 ∈ dom 𝑥𝐴 𝐵 ↔ ∃𝑥𝐴𝑣𝑢, 𝑣⟩ ∈ 𝐵)
48 eliun 4950 . . . . . 6 (𝑢 𝑥𝐴 𝐷 ↔ ∃𝑥𝐴 𝑢𝐷)
4942, 47, 483bitr4g 314 . . . . 5 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → (𝑢 ∈ dom 𝑥𝐴 𝐵𝑢 𝑥𝐴 𝐷))
5049eqrdv 2734 . . . 4 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → dom 𝑥𝐴 𝐵 = 𝑥𝐴 𝐷)
51 df-fn 6495 . . . 4 ( 𝑥𝐴 𝐵 Fn 𝑥𝐴 𝐷 ↔ (Fun 𝑥𝐴 𝐵 ∧ dom 𝑥𝐴 𝐵 = 𝑥𝐴 𝐷))
5236, 50, 51sylanbrc 583 . . 3 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵 Fn 𝑥𝐴 𝐷)
53 rniun 6105 . . . 4 ran 𝑥𝐴 𝐵 = 𝑥𝐴 ran 𝐵
5420frnd 6670 . . . . . . 7 (𝐵:𝐷1-1𝑆 → ran 𝐵𝑆)
5554adantr 480 . . . . . 6 ((𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ran 𝐵𝑆)
5655ralimi 3073 . . . . 5 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ∀𝑥𝐴 ran 𝐵𝑆)
57 iunss 5000 . . . . 5 ( 𝑥𝐴 ran 𝐵𝑆 ↔ ∀𝑥𝐴 ran 𝐵𝑆)
5856, 57sylibr 234 . . . 4 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 ran 𝐵𝑆)
5953, 58eqsstrid 3972 . . 3 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → ran 𝑥𝐴 𝐵𝑆)
60 df-f 6496 . . 3 ( 𝑥𝐴 𝐵: 𝑥𝐴 𝐷𝑆 ↔ ( 𝑥𝐴 𝐵 Fn 𝑥𝐴 𝐷 ∧ ran 𝑥𝐴 𝐵𝑆))
6152, 59, 60sylanbrc 583 . 2 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵: 𝑥𝐴 𝐷𝑆)
6231simprd 495 . . 3 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
6334cnveqi 5823 . . . 4 𝑥𝐴 𝐵 = {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵}
6463funeqi 6513 . . 3 (Fun 𝑥𝐴 𝐵 ↔ Fun {𝑧 ∣ ∃𝑥𝐴 𝑧 = 𝐵})
6562, 64sylibr 234 . 2 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → Fun 𝑥𝐴 𝐵)
66 df-f1 6497 . 2 ( 𝑥𝐴 𝐵: 𝑥𝐴 𝐷1-1𝑆 ↔ ( 𝑥𝐴 𝐵: 𝑥𝐴 𝐷𝑆 ∧ Fun 𝑥𝐴 𝐵))
6761, 65, 66sylanbrc 583 1 (∀𝑥𝐴 (𝐵:𝐷1-1𝑆 ∧ ∀𝑦𝐴 (𝐵𝐶𝐶𝐵)) → 𝑥𝐴 𝐵: 𝑥𝐴 𝐷1-1𝑆)
Colors of variables: wff setvar class
Syntax hints:  wi 4  wb 206  wa 395  wo 847   = wceq 1541  wex 1780  wcel 2113  {cab 2714  wral 3051  wrex 3060  Vcvv 3440  wss 3901  cop 4586   cuni 4863   ciun 4946  ccnv 5623  dom cdm 5624  ran crn 5625  Fun wfun 6486   Fn wfn 6487  wf 6488  1-1wf1 6489
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 1911  ax-6 1968  ax-7 2009  ax-8 2115  ax-9 2123  ax-10 2146  ax-11 2162  ax-12 2184  ax-ext 2708  ax-sep 5241  ax-nul 5251  ax-pow 5310  ax-pr 5377  ax-un 7680
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 848  df-3an 1088  df-tru 1544  df-fal 1554  df-ex 1781  df-nf 1785  df-sb 2068  df-clab 2715  df-cleq 2728  df-clel 2811  df-nfc 2885  df-ral 3052  df-rex 3061  df-rab 3400  df-v 3442  df-dif 3904  df-un 3906  df-in 3908  df-ss 3918  df-nul 4286  df-if 4480  df-pw 4556  df-sn 4581  df-pr 4583  df-op 4587  df-uni 4864  df-iun 4948  df-br 5099  df-opab 5161  df-id 5519  df-xp 5630  df-rel 5631  df-cnv 5632  df-co 5633  df-dm 5634  df-rn 5635  df-fun 6494  df-fn 6495  df-f 6496  df-f1 6497
This theorem is referenced by:  ackbij2  10152
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