Theorem rab0 3572

Description: Any restricted class abstraction restricted to the empty set is empty. (Contributed by NM, 15-Oct-2003.) (Proof shortened by Andrew Salmon, 26-Jun-2011.)

Assertion

Ref	Expression
rab0	⊢ {x ∈ ∅ ∣ φ} = ∅

Proof of Theorem rab0

Step	Hyp	Ref	Expression
1		equid 1676	. . . . 5 ⊢ x = x
2		noel 3555	. . . . . 6 ⊢ ¬ x ∈ ∅
3	2	intnanr 881	. . . . 5 ⊢ ¬ (x ∈ ∅ ∧ φ)
4	1, 3	2th 230	. . . 4 ⊢ (x = x ↔ ¬ (x ∈ ∅ ∧ φ))
5	4	con2bii 322	. . 3 ⊢ ((x ∈ ∅ ∧ φ) ↔ ¬ x = x)
6	5	abbii 2466	. 2 ⊢ {x ∣ (x ∈ ∅ ∧ φ)} = {x ∣ ¬ x = x}
7		df-rab 2624	. 2 ⊢ {x ∈ ∅ ∣ φ} = {x ∣ (x ∈ ∅ ∧ φ)}
8		dfnul2 3553	. 2 ⊢ ∅ = {x ∣ ¬ x = x}
9	6, 7, 8	3eqtr4i 2383	1 ⊢ {x ∈ ∅ ∣ φ} = ∅

Syntax hints:  ¬ wn 3   ∧ wa 358   = wceq 1642   ∈ wcel 1710  {cab 2339  {crab 2619  ∅c0 3551

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1546  ax-5 1557  ax-17 1616  ax-9 1654  ax-8 1675  ax-6 1729  ax-7 1734  ax-11 1746  ax-12 1925  ax-ext 2334

This theorem depends on definitions:  df-bi 177  df-or 359  df-an 360  df-nan 1288  df-tru 1319  df-ex 1542  df-nf 1545  df-sb 1649  df-clab 2340  df-cleq 2346  df-clel 2349  df-nfc 2479  df-rab 2624  df-v 2862  df-nin 3212  df-compl 3213  df-in 3214  df-dif 3216  df-nul 3552

This theorem is referenced by: (None)