Metamath Proof Explorer


Theorem iinexd

Description: The existence of an indexed union. x is normally a free-variable parameter in B , which should be read B ( x ) . (Contributed by Glauco Siliprandi, 23-Oct-2021)

Ref Expression
Hypotheses iinexd.1 ( 𝜑𝐴 ≠ ∅ )
iinexd.2 ( 𝜑 → ∀ 𝑥𝐴 𝐵𝐶 )
Assertion iinexd ( 𝜑 𝑥𝐴 𝐵 ∈ V )

Proof

Step Hyp Ref Expression
1 iinexd.1 ( 𝜑𝐴 ≠ ∅ )
2 iinexd.2 ( 𝜑 → ∀ 𝑥𝐴 𝐵𝐶 )
3 iinexg ( ( 𝐴 ≠ ∅ ∧ ∀ 𝑥𝐴 𝐵𝐶 ) → 𝑥𝐴 𝐵 ∈ V )
4 1 2 3 syl2anc ( 𝜑 𝑥𝐴 𝐵 ∈ V )