Theorem pw0 4816

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.)

Assertion

Ref	Expression
pw0	⊢ 𝒫 ∅ = {∅}

Proof of Theorem pw0

Step	Hyp	Ref	Expression
1		ss0b 4398	. . 3 ⊢ (𝑥 ⊆ ∅ ↔ 𝑥 = ∅)
2	1	abbii 2803	. 2 ⊢ {𝑥 ∣ 𝑥 ⊆ ∅} = {𝑥 ∣ 𝑥 = ∅}
3		df-pw 4605	. 2 ⊢ 𝒫 ∅ = {𝑥 ∣ 𝑥 ⊆ ∅}
4		df-sn 4630	. 2 ⊢ {∅} = {𝑥 ∣ 𝑥 = ∅}
5	2, 3, 4	3eqtr4i 2771	1 ⊢ 𝒫 ∅ = {∅}

Syntax hints:   = wceq 1542  {cab 2710   ⊆ wss 3949  ∅c0 4323  𝒫 cpw 4603  {csn 4629

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1798  ax-4 1812  ax-5 1914  ax-6 1972  ax-7 2012  ax-8 2109  ax-9 2117  ax-ext 2704

This theorem depends on definitions:  df-bi 206  df-an 398  df-tru 1545  df-fal 1555  df-ex 1783  df-sb 2069  df-clab 2711  df-cleq 2725  df-clel 2811  df-v 3477  df-dif 3952  df-in 3956  df-ss 3966  df-nul 4324  df-pw 4605  df-sn 4630

This theorem is referenced by:  p0ex  5383  pwfi  9178  pwfiOLD  9347  ackbij1lem14  10228  fin1a2lem12  10406  0tsk  10750  hashbc  14412  incexclem  15782  sn0topon  22501  sn0cld  22594  ust0  23724  made0  27368  uhgr0vb  28332  uhgr0  28333  esumnul  33046  rankeq1o  35143  ssoninhaus  35333  sge00  45092