Theorem disjx0 5052

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 4349	. 2 ⊢ ∅ ⊆ {∅}
2		disjxsn 5051	. 2 ⊢ Disj 𝑥 ∈ {∅}𝐵
3		disjss1 5029	. 2 ⊢ (∅ ⊆ {∅} → (Disj 𝑥 ∈ {∅}𝐵 → Disj 𝑥 ∈ ∅ 𝐵))
4	1, 2, 3	mp2 9	1 ⊢ Disj 𝑥 ∈ ∅ 𝐵

Syntax hints:   ⊆ wss 3935  ∅c0 4290  {csn 4560  Disj wdisj 5023

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1792  ax-4 1806  ax-5 1907  ax-6 1966  ax-7 2011  ax-8 2112  ax-9 2120  ax-10 2141  ax-11 2157  ax-12 2173  ax-ext 2793

This theorem depends on definitions:  df-bi 209  df-an 399  df-or 844  df-tru 1536  df-ex 1777  df-nf 1781  df-sb 2066  df-mo 2618  df-clab 2800  df-cleq 2814  df-clel 2893  df-nfc 2963  df-rmo 3146  df-dif 3938  df-in 3942  df-ss 3951  df-nul 4291  df-sn 4561  df-disj 5024

This theorem is referenced by: (None)