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Theorem iunab 4711
Description: The indexed union of a class abstraction. (Contributed by NM, 27-Dec-2004.)
Assertion
Ref Expression
iunab 𝑥𝐴 {𝑦𝜑} = {𝑦 ∣ ∃𝑥𝐴 𝜑}
Distinct variable groups:   𝑦,𝐴   𝑥,𝑦
Allowed substitution hints:   𝜑(𝑥,𝑦)   𝐴(𝑥)

Proof of Theorem iunab
StepHypRef Expression
1 nfcv 2916 . . . 4 𝑦𝐴
2 nfab1 2918 . . . 4 𝑦{𝑦𝜑}
31, 2nfiun 4693 . . 3 𝑦 𝑥𝐴 {𝑦𝜑}
4 nfab1 2918 . . 3 𝑦{𝑦 ∣ ∃𝑥𝐴 𝜑}
53, 4cleqf 2942 . 2 ( 𝑥𝐴 {𝑦𝜑} = {𝑦 ∣ ∃𝑥𝐴 𝜑} ↔ ∀𝑦(𝑦 𝑥𝐴 {𝑦𝜑} ↔ 𝑦 ∈ {𝑦 ∣ ∃𝑥𝐴 𝜑}))
6 abid 2762 . . . 4 (𝑦 ∈ {𝑦𝜑} ↔ 𝜑)
76rexbii 3193 . . 3 (∃𝑥𝐴 𝑦 ∈ {𝑦𝜑} ↔ ∃𝑥𝐴 𝜑)
8 eliun 4669 . . 3 (𝑦 𝑥𝐴 {𝑦𝜑} ↔ ∃𝑥𝐴 𝑦 ∈ {𝑦𝜑})
9 abid 2762 . . 3 (𝑦 ∈ {𝑦 ∣ ∃𝑥𝐴 𝜑} ↔ ∃𝑥𝐴 𝜑)
107, 8, 93bitr4i 293 . 2 (𝑦 𝑥𝐴 {𝑦𝜑} ↔ 𝑦 ∈ {𝑦 ∣ ∃𝑥𝐴 𝜑})
115, 10mpgbir 1877 1 𝑥𝐴 {𝑦𝜑} = {𝑦 ∣ ∃𝑥𝐴 𝜑}
Colors of variables: wff setvar class
Syntax hints:  wb 197   = wceq 1634  wcel 2148  {cab 2760  wrex 3065   ciun 4665
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1873  ax-4 1888  ax-5 1994  ax-6 2060  ax-7 2096  ax-9 2157  ax-10 2177  ax-11 2193  ax-12 2206  ax-13 2411  ax-ext 2754
This theorem depends on definitions:  df-bi 198  df-an 384  df-or 864  df-tru 1637  df-ex 1856  df-nf 1861  df-sb 2053  df-clab 2761  df-cleq 2767  df-clel 2770  df-nfc 2905  df-ral 3069  df-rex 3070  df-v 3357  df-iun 4667
This theorem is referenced by:  iunrab  4712  iunid  4720  dfimafn2  6405  rabiun  33732  dfaimafn2  41791  rnfdmpr  41847
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