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Theorem iuncld 23053
Description: A finite indexed union of closed sets is closed. (Contributed by Mario Carneiro, 19-Sep-2015.)
Hypothesis
Ref Expression
clscld.1 𝑋 = 𝐽
Assertion
Ref Expression
iuncld ((𝐽 ∈ Top ∧ 𝐴 ∈ Fin ∧ ∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽)) → 𝑥𝐴 𝐵 ∈ (Clsd‘𝐽))
Distinct variable groups:   𝑥,𝐽   𝑥,𝑋   𝑥,𝐴
Allowed substitution hint:   𝐵(𝑥)

Proof of Theorem iuncld
StepHypRef Expression
1 difin 4272 . . . 4 (𝑋 ∖ (𝑋 𝑥𝐴 (𝑋𝐵))) = (𝑋 𝑥𝐴 (𝑋𝐵))
2 iundif2 5074 . . . 4 𝑥𝐴 (𝑋 ∖ (𝑋𝐵)) = (𝑋 𝑥𝐴 (𝑋𝐵))
31, 2eqtr4i 2768 . . 3 (𝑋 ∖ (𝑋 𝑥𝐴 (𝑋𝐵))) = 𝑥𝐴 (𝑋 ∖ (𝑋𝐵))
4 clscld.1 . . . . . . . 8 𝑋 = 𝐽
54cldss 23037 . . . . . . 7 (𝐵 ∈ (Clsd‘𝐽) → 𝐵𝑋)
6 dfss4 4269 . . . . . . 7 (𝐵𝑋 ↔ (𝑋 ∖ (𝑋𝐵)) = 𝐵)
75, 6sylib 218 . . . . . 6 (𝐵 ∈ (Clsd‘𝐽) → (𝑋 ∖ (𝑋𝐵)) = 𝐵)
87ralimi 3083 . . . . 5 (∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽) → ∀𝑥𝐴 (𝑋 ∖ (𝑋𝐵)) = 𝐵)
983ad2ant3 1136 . . . 4 ((𝐽 ∈ Top ∧ 𝐴 ∈ Fin ∧ ∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽)) → ∀𝑥𝐴 (𝑋 ∖ (𝑋𝐵)) = 𝐵)
10 iuneq2 5011 . . . 4 (∀𝑥𝐴 (𝑋 ∖ (𝑋𝐵)) = 𝐵 𝑥𝐴 (𝑋 ∖ (𝑋𝐵)) = 𝑥𝐴 𝐵)
119, 10syl 17 . . 3 ((𝐽 ∈ Top ∧ 𝐴 ∈ Fin ∧ ∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽)) → 𝑥𝐴 (𝑋 ∖ (𝑋𝐵)) = 𝑥𝐴 𝐵)
123, 11eqtrid 2789 . 2 ((𝐽 ∈ Top ∧ 𝐴 ∈ Fin ∧ ∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽)) → (𝑋 ∖ (𝑋 𝑥𝐴 (𝑋𝐵))) = 𝑥𝐴 𝐵)
13 simp1 1137 . . 3 ((𝐽 ∈ Top ∧ 𝐴 ∈ Fin ∧ ∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽)) → 𝐽 ∈ Top)
144cldopn 23039 . . . . 5 (𝐵 ∈ (Clsd‘𝐽) → (𝑋𝐵) ∈ 𝐽)
1514ralimi 3083 . . . 4 (∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽) → ∀𝑥𝐴 (𝑋𝐵) ∈ 𝐽)
164riinopn 22914 . . . 4 ((𝐽 ∈ Top ∧ 𝐴 ∈ Fin ∧ ∀𝑥𝐴 (𝑋𝐵) ∈ 𝐽) → (𝑋 𝑥𝐴 (𝑋𝐵)) ∈ 𝐽)
1715, 16syl3an3 1166 . . 3 ((𝐽 ∈ Top ∧ 𝐴 ∈ Fin ∧ ∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽)) → (𝑋 𝑥𝐴 (𝑋𝐵)) ∈ 𝐽)
184opncld 23041 . . 3 ((𝐽 ∈ Top ∧ (𝑋 𝑥𝐴 (𝑋𝐵)) ∈ 𝐽) → (𝑋 ∖ (𝑋 𝑥𝐴 (𝑋𝐵))) ∈ (Clsd‘𝐽))
1913, 17, 18syl2anc 584 . 2 ((𝐽 ∈ Top ∧ 𝐴 ∈ Fin ∧ ∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽)) → (𝑋 ∖ (𝑋 𝑥𝐴 (𝑋𝐵))) ∈ (Clsd‘𝐽))
2012, 19eqeltrrd 2842 1 ((𝐽 ∈ Top ∧ 𝐴 ∈ Fin ∧ ∀𝑥𝐴 𝐵 ∈ (Clsd‘𝐽)) → 𝑥𝐴 𝐵 ∈ (Clsd‘𝐽))
Colors of variables: wff setvar class
Syntax hints:  wi 4  w3a 1087   = wceq 1540  wcel 2108  wral 3061  cdif 3948  cin 3950  wss 3951   cuni 4907   ciun 4991   ciin 4992  cfv 6561  Fincfn 8985  Topctop 22899  Clsdccld 23024
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2007  ax-8 2110  ax-9 2118  ax-10 2141  ax-11 2157  ax-12 2177  ax-ext 2708  ax-sep 5296  ax-nul 5306  ax-pow 5365  ax-pr 5432  ax-un 7755
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 849  df-3or 1088  df-3an 1089  df-tru 1543  df-fal 1553  df-ex 1780  df-nf 1784  df-sb 2065  df-mo 2540  df-eu 2569  df-clab 2715  df-cleq 2729  df-clel 2816  df-nfc 2892  df-ne 2941  df-ral 3062  df-rex 3071  df-reu 3381  df-rab 3437  df-v 3482  df-sbc 3789  df-dif 3954  df-un 3956  df-in 3958  df-ss 3968  df-pss 3971  df-nul 4334  df-if 4526  df-pw 4602  df-sn 4627  df-pr 4629  df-op 4633  df-uni 4908  df-int 4947  df-iun 4993  df-iin 4994  df-br 5144  df-opab 5206  df-mpt 5226  df-tr 5260  df-id 5578  df-eprel 5584  df-po 5592  df-so 5593  df-fr 5637  df-we 5639  df-xp 5691  df-rel 5692  df-cnv 5693  df-co 5694  df-dm 5695  df-rn 5696  df-res 5697  df-ima 5698  df-ord 6387  df-on 6388  df-lim 6389  df-suc 6390  df-iota 6514  df-fun 6563  df-fn 6564  df-f 6565  df-f1 6566  df-fo 6567  df-f1o 6568  df-fv 6569  df-om 7888  df-1st 8014  df-2nd 8015  df-1o 8506  df-2o 8507  df-en 8986  df-dom 8987  df-fin 8989  df-top 22900  df-cld 23027
This theorem is referenced by:  unicld  23054  t1ficld  23335  mblfinlem1  37664  mblfinlem2  37665
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