Metamath Proof Explorer


Theorem qsexg

Description: A quotient set exists. (Contributed by FL, 19-May-2007) (Revised by Mario Carneiro, 9-Jul-2014)

Ref Expression
Assertion qsexg ( 𝐴 ∈ 𝑉 → ( 𝐴 / 𝑅 ) ∈ V )

Proof

Step Hyp Ref Expression
1 df-qs ⊢ ( 𝐴 / 𝑅 ) = { 𝑦 ∣ ∃ 𝑥 ∈ 𝐴 𝑦 = [ 𝑥 ] 𝑅 }
2 abrexexg ⊢ ( 𝐴 ∈ 𝑉 → { 𝑦 ∣ ∃ 𝑥 ∈ 𝐴 𝑦 = [ 𝑥 ] 𝑅 } ∈ V )
3 1 2 eqeltrid ⊢ ( 𝐴 ∈ 𝑉 → ( 𝐴 / 𝑅 ) ∈ V )