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| Mirrors > Home > ILE Home > Th. List > vpwex | GIF version | ||
| 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 4270 from vpwex 4269. (Revised by BJ, 10-Aug-2022.) |
| Ref | Expression |
|---|---|
| vpwex | ⊢ 𝒫 𝑥 ∈ V |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | df-pw 3654 | . 2 ⊢ 𝒫 𝑥 = {𝑦 ∣ 𝑦 ⊆ 𝑥} | |
| 2 | axpow2 4266 | . . . . 5 ⊢ ∃𝑧∀𝑦(𝑦 ⊆ 𝑥 → 𝑦 ∈ 𝑧) | |
| 3 | 2 | bm1.3ii 4210 | . . . 4 ⊢ ∃𝑧∀𝑦(𝑦 ∈ 𝑧 ↔ 𝑦 ⊆ 𝑥) |
| 4 | abeq2 2340 | . . . . 5 ⊢ (𝑧 = {𝑦 ∣ 𝑦 ⊆ 𝑥} ↔ ∀𝑦(𝑦 ∈ 𝑧 ↔ 𝑦 ⊆ 𝑥)) | |
| 5 | 4 | exbii 1653 | . . . 4 ⊢ (∃𝑧 𝑧 = {𝑦 ∣ 𝑦 ⊆ 𝑥} ↔ ∃𝑧∀𝑦(𝑦 ∈ 𝑧 ↔ 𝑦 ⊆ 𝑥)) |
| 6 | 3, 5 | mpbir 146 | . . 3 ⊢ ∃𝑧 𝑧 = {𝑦 ∣ 𝑦 ⊆ 𝑥} |
| 7 | 6 | issetri 2812 | . 2 ⊢ {𝑦 ∣ 𝑦 ⊆ 𝑥} ∈ V |
| 8 | 1, 7 | eqeltri 2304 | 1 ⊢ 𝒫 𝑥 ∈ V |
| Colors of variables: wff set class |
| Syntax hints: ↔ wb 105 ∀wal 1395 = wceq 1397 ∃wex 1540 ∈ wcel 2202 {cab 2217 Vcvv 2802 ⊆ wss 3200 𝒫 cpw 3652 |
| 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 1495 ax-7 1496 ax-gen 1497 ax-ie1 1541 ax-ie2 1542 ax-8 1552 ax-11 1554 ax-4 1558 ax-17 1574 ax-i9 1578 ax-ial 1582 ax-i5r 1583 ax-14 2205 ax-ext 2213 ax-sep 4207 ax-pow 4264 |
| This theorem depends on definitions: df-bi 117 df-nf 1509 df-sb 1811 df-clab 2218 df-cleq 2224 df-clel 2227 df-v 2804 df-in 3206 df-ss 3213 df-pw 3654 |
| This theorem is referenced by: pwexg 4270 pwnex 4546 exmidpw2en 7103 metuex 14568 istopon 14736 dmtopon 14746 tgdom 14795 |
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