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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 3551 | . 2 ⊢ ∅ ⊆ 𝐴 | |
| 2 | 0ex 4242 | . . 3 ⊢ ∅ ∈ V | |
| 3 | 2 | elpw 3680 | . 2 ⊢ (∅ ∈ 𝒫 𝐴 ↔ ∅ ⊆ 𝐴) |
| 4 | 1, 3 | mpbir 146 | 1 ⊢ ∅ ∈ 𝒫 𝐴 |
| Colors of variables: wff set class |
| Syntax hints: ∈ wcel 2205 ⊆ wss 3214 ∅c0 3512 𝒫 cpw 3674 |
| 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 619 ax-in2 620 ax-io 717 ax-5 1496 ax-7 1497 ax-gen 1498 ax-ie1 1542 ax-ie2 1543 ax-8 1553 ax-10 1554 ax-11 1555 ax-i12 1556 ax-bndl 1558 ax-4 1559 ax-17 1575 ax-i9 1579 ax-ial 1583 ax-i5r 1584 ax-ext 2216 ax-nul 4241 |
| This theorem depends on definitions: df-bi 117 df-tru 1401 df-nf 1510 df-sb 1812 df-clab 2221 df-cleq 2227 df-clel 2230 df-nfc 2375 df-v 2817 df-dif 3216 df-in 3220 df-ss 3227 df-nul 3513 df-pw 3676 |
| This theorem is referenced by: ordpwsucexmid 4697 pw1on 7549 pw1ne0 7551 ssenneg 11229 eupth2lemsfi 16585 pw1nct 16889 exmidpeirce 16893 |
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