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Mirrors > Home > ILE Home > Th. List > pw0 | GIF version |
Description: Compute the power set of the empty set. Theorem 89 of [Suppes] p. 47. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Andrew Salmon, 29-Jun-2011.) |
Ref | Expression |
---|---|
pw0 | ⊢ 𝒫 ∅ = {∅} |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ss0b 3397 | . . 3 ⊢ (𝑥 ⊆ ∅ ↔ 𝑥 = ∅) | |
2 | 1 | abbii 2253 | . 2 ⊢ {𝑥 ∣ 𝑥 ⊆ ∅} = {𝑥 ∣ 𝑥 = ∅} |
3 | df-pw 3507 | . 2 ⊢ 𝒫 ∅ = {𝑥 ∣ 𝑥 ⊆ ∅} | |
4 | df-sn 3528 | . 2 ⊢ {∅} = {𝑥 ∣ 𝑥 = ∅} | |
5 | 2, 3, 4 | 3eqtr4i 2168 | 1 ⊢ 𝒫 ∅ = {∅} |
Colors of variables: wff set class |
Syntax hints: = wceq 1331 {cab 2123 ⊆ wss 3066 ∅c0 3358 𝒫 cpw 3505 {csn 3522 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 603 ax-in2 604 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-bndl 1486 ax-4 1487 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2119 |
This theorem depends on definitions: df-bi 116 df-tru 1334 df-nf 1437 df-sb 1736 df-clab 2124 df-cleq 2130 df-clel 2133 df-nfc 2268 df-v 2683 df-dif 3068 df-in 3072 df-ss 3079 df-nul 3359 df-pw 3507 df-sn 3528 |
This theorem is referenced by: p0ex 4107 sn0topon 12246 sn0cld 12295 |
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