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Theorem vpwex 4212
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 4213 from vpwex 4212. (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 3607 . 2 𝒫 𝑥 = {𝑦𝑦𝑥}
2 axpow2 4209 . . . . 5 𝑧𝑦(𝑦𝑥𝑦𝑧)
32bm1.3ii 4154 . . . 4 𝑧𝑦(𝑦𝑧𝑦𝑥)
4 abeq2 2305 . . . . 5 (𝑧 = {𝑦𝑦𝑥} ↔ ∀𝑦(𝑦𝑧𝑦𝑥))
54exbii 1619 . . . 4 (∃𝑧 𝑧 = {𝑦𝑦𝑥} ↔ ∃𝑧𝑦(𝑦𝑧𝑦𝑥))
63, 5mpbir 146 . . 3 𝑧 𝑧 = {𝑦𝑦𝑥}
76issetri 2772 . 2 {𝑦𝑦𝑥} ∈ V
81, 7eqeltri 2269 1 𝒫 𝑥 ∈ V
Colors of variables: wff set class
Syntax hints:  wb 105  wal 1362   = wceq 1364  wex 1506  wcel 2167  {cab 2182  Vcvv 2763  wss 3157  𝒫 cpw 3605
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 1461  ax-7 1462  ax-gen 1463  ax-ie1 1507  ax-ie2 1508  ax-8 1518  ax-11 1520  ax-4 1524  ax-17 1540  ax-i9 1544  ax-ial 1548  ax-i5r 1549  ax-14 2170  ax-ext 2178  ax-sep 4151  ax-pow 4207
This theorem depends on definitions:  df-bi 117  df-nf 1475  df-sb 1777  df-clab 2183  df-cleq 2189  df-clel 2192  df-v 2765  df-in 3163  df-ss 3170  df-pw 3607
This theorem is referenced by:  pwexg  4213  pwnex  4484  exmidpw2en  6973  metuex  14111  istopon  14249  dmtopon  14259  tgdom  14308
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