Theorem disjx0 5119

Description: An empty collection is disjoint. (Contributed by Mario Carneiro, 14-Nov-2016.)

Assertion

Ref	Expression
disjx0	⊢ Disj 𝑥 ∈ ∅ 𝐵

Proof of Theorem disjx0

Step	Hyp	Ref	Expression
1		0ss 4380	. 2 ⊢ ∅ ⊆ {∅}
2		disjxsn 5118	. 2 ⊢ Disj 𝑥 ∈ {∅}𝐵
3		disjss1 5097	. 2 ⊢ (∅ ⊆ {∅} → (Disj 𝑥 ∈ {∅}𝐵 → Disj 𝑥 ∈ ∅ 𝐵))
4	1, 2, 3	mp2 9	1 ⊢ Disj 𝑥 ∈ ∅ 𝐵

Syntax hints:   ⊆ wss 3931  ∅c0 4313  {csn 4606  Disj wdisj 5091

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1795  ax-4 1809  ax-5 1910  ax-6 1967  ax-7 2008  ax-8 2111  ax-9 2119  ax-ext 2708

This theorem depends on definitions:  df-bi 207  df-an 396  df-tru 1543  df-fal 1553  df-ex 1780  df-sb 2066  df-mo 2540  df-clab 2715  df-cleq 2728  df-clel 2810  df-rmo 3364  df-dif 3934  df-ss 3948  df-nul 4314  df-sn 4607  df-disj 5092

This theorem is referenced by: (None)