Theorem wunin 10798

Description: A weak universe is closed under binary intersections. (Contributed by Mario Carneiro, 2-Jan-2017.)

Hypotheses

Ref	Expression
wununi.1	⊢ (𝜑 → 𝑈 ∈ WUni)
wununi.2	⊢ (𝜑 → 𝐴 ∈ 𝑈)

Assertion

Ref	Expression
wunin	⊢ (𝜑 → (𝐴 ∩ 𝐵) ∈ 𝑈)

Proof of Theorem wunin

Step	Hyp	Ref	Expression
1		wununi.1	. 2 ⊢ (𝜑 → 𝑈 ∈ WUni)
2		wununi.2	. 2 ⊢ (𝜑 → 𝐴 ∈ 𝑈)
3		inss1 4182	. . 3 ⊢ (𝐴 ∩ 𝐵) ⊆ 𝐴
4	3	a1i 11	. 2 ⊢ (𝜑 → (𝐴 ∩ 𝐵) ⊆ 𝐴)
5	1, 2, 4	wunss 10797	1 ⊢ (𝜑 → (𝐴 ∩ 𝐵) ∈ 𝑈)

This proof depends on syntax axioms:   → wi 4   ∈ wcel 2145   ∩ cin 3898   ⊆ wss 3899  WUnicwun 10785

This proof depends on axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1828  ax-4 1842  ax-5 1943  ax-6 2000  ax-7 2041  ax-8 2147  ax-9 2155  ax-ext 2733  ax-sep 5249

This proof depends on definitions:  df-bi 210  df-an 402  df-3an 1105  df-tru 1573  df-ex 1813  df-sb 2100  df-clab 2740  df-cleq 2753  df-clel 2836  df-ne 2957  df-ral 3078  df-rex 3088  df-rab 3414  df-v 3453  df-in 3906  df-ss 3916  df-pw 4559  df-uni 4868  df-tr 5213  df-wun 10787

This theorem is used by:  wunress  17427