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| Mirrors > Home > ILE Home > Th. List > 0elpw | GIF version | ||
| Description: Every power class contains the empty set. (Contributed by NM, 25-Oct-2007.) |
| Ref | Expression |
|---|---|
| 0elpw | ⊢ ∅ ∈ 𝒫 𝐴 |
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | 0ss 3489 | . 2 ⊢ ∅ ⊆ 𝐴 | |
| 2 | 0ex 4160 | . . 3 ⊢ ∅ ∈ V | |
| 3 | 2 | elpw 3611 | . 2 ⊢ (∅ ∈ 𝒫 𝐴 ↔ ∅ ⊆ 𝐴) |
| 4 | 1, 3 | mpbir 146 | 1 ⊢ ∅ ∈ 𝒫 𝐴 |
| Colors of variables: wff set class |
| Syntax hints: ∈ wcel 2167 ⊆ wss 3157 ∅c0 3450 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-in1 615 ax-in2 616 ax-io 710 ax-5 1461 ax-7 1462 ax-gen 1463 ax-ie1 1507 ax-ie2 1508 ax-8 1518 ax-10 1519 ax-11 1520 ax-i12 1521 ax-bndl 1523 ax-4 1524 ax-17 1540 ax-i9 1544 ax-ial 1548 ax-i5r 1549 ax-ext 2178 ax-nul 4159 |
| This theorem depends on definitions: df-bi 117 df-tru 1367 df-nf 1475 df-sb 1777 df-clab 2183 df-cleq 2189 df-clel 2192 df-nfc 2328 df-v 2765 df-dif 3159 df-in 3163 df-ss 3170 df-nul 3451 df-pw 3607 |
| This theorem is referenced by: ordpwsucexmid 4606 pw1on 7293 pw1ne0 7295 pw1nct 15647 |
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