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Theorem vpwex 4275
Description: Power set axiom: the powerclass of a set is a set. Axiom 4 of [TakeutiZaring] p. 17. (Contributed by NM, 30-Oct-2003.) (Proof shortened by Andrew Salmon, 25-Jul-2011.) Revised to prove pwexg 4276 from vpwex 4275. (Revised by BJ, 10-Aug-2022.)
Assertion
Ref Expression
vpwex 𝒫 𝑥 ∈ V

Proof of Theorem vpwex
Dummy variables 𝑦 𝑧 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 df-pw 3658 . 2 𝒫 𝑥 = {𝑦𝑦𝑥}
2 axpow2 4272 . . . . 5 𝑧𝑦(𝑦𝑥𝑦𝑧)
32bm1.3ii 4215 . . . 4 𝑧𝑦(𝑦𝑧𝑦𝑥)
4 abeq2 2340 . . . . 5 (𝑧 = {𝑦𝑦𝑥} ↔ ∀𝑦(𝑦𝑧𝑦𝑥))
54exbii 1654 . . . 4 (∃𝑧 𝑧 = {𝑦𝑦𝑥} ↔ ∃𝑧𝑦(𝑦𝑧𝑦𝑥))
63, 5mpbir 146 . . 3 𝑧 𝑧 = {𝑦𝑦𝑥}
76issetri 2813 . 2 {𝑦𝑦𝑥} ∈ V
81, 7eqeltri 2304 1 𝒫 𝑥 ∈ V
Colors of variables: wff set class
Syntax hints:  wb 105  wal 1396   = wceq 1398  wex 1541  wcel 2202  {cab 2217  Vcvv 2803  wss 3201  𝒫 cpw 3656
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-ia1 106  ax-ia2 107  ax-ia3 108  ax-5 1496  ax-7 1497  ax-gen 1498  ax-ie1 1542  ax-ie2 1543  ax-8 1553  ax-11 1555  ax-4 1559  ax-17 1575  ax-i9 1579  ax-ial 1583  ax-i5r 1584  ax-14 2205  ax-ext 2213  ax-sep 4212  ax-pow 4270
This theorem depends on definitions:  df-bi 117  df-nf 1510  df-sb 1811  df-clab 2218  df-cleq 2224  df-clel 2227  df-v 2805  df-in 3207  df-ss 3214  df-pw 3658
This theorem is referenced by:  pwexg  4276  pwnex  4552  exmidpw2en  7147  metuex  14634  istopon  14807  dmtopon  14817  tgdom  14866
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