Theorem wunin 10124

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 4155	. . 3 ⊢ (𝐴 ∩ 𝐵) ⊆ 𝐴
4	3	a1i 11	. 2 ⊢ (𝜑 → (𝐴 ∩ 𝐵) ⊆ 𝐴)
5	1, 2, 4	wunss 10123	1 ⊢ (𝜑 → (𝐴 ∩ 𝐵) ∈ 𝑈)

Syntax hints:   → wi 4   ∈ wcel 2111   ∩ cin 3880   ⊆ wss 3881  WUnicwun 10111

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-11 2158  ax-ext 2770  ax-sep 5167

This theorem depends on definitions:  df-bi 210  df-an 400  df-3an 1086  df-tru 1541  df-ex 1782  df-sb 2070  df-clab 2777  df-cleq 2791  df-clel 2870  df-ne 2988  df-ral 3111  df-rab 3115  df-v 3443  df-in 3888  df-ss 3898  df-pw 4499  df-uni 4801  df-tr 5137  df-wun 10113

This theorem is referenced by:  wunress  16556