Metamath Proof Explorer


Theorem collexd

Description: The output of the collection operation is a set if the second input is. (Contributed by Rohan Ridenour, 11-Aug-2023)

Ref Expression
Hypothesis collexd.1 ( 𝜑𝐴𝑉 )
Assertion collexd ( 𝜑 → ( 𝐹 Coll 𝐴 ) ∈ V )

Proof

Step Hyp Ref Expression
1 collexd.1 ( 𝜑𝐴𝑉 )
2 df-coll ( 𝐹 Coll 𝐴 ) = 𝑥𝐴 Scott ( 𝐹 “ { 𝑥 } )
3 scottex2 Scott ( 𝐹 “ { 𝑥 } ) ∈ V
4 3 a1i ( 𝜑 → Scott ( 𝐹 “ { 𝑥 } ) ∈ V )
5 4 ralrimivw ( 𝜑 → ∀ 𝑥𝐴 Scott ( 𝐹 “ { 𝑥 } ) ∈ V )
6 iunexg ( ( 𝐴𝑉 ∧ ∀ 𝑥𝐴 Scott ( 𝐹 “ { 𝑥 } ) ∈ V ) → 𝑥𝐴 Scott ( 𝐹 “ { 𝑥 } ) ∈ V )
7 1 5 6 syl2anc ( 𝜑 𝑥𝐴 Scott ( 𝐹 “ { 𝑥 } ) ∈ V )
8 2 7 eqeltrid ( 𝜑 → ( 𝐹 Coll 𝐴 ) ∈ V )