Metamath Proof Explorer


Theorem elriin

Description: Elementhood in a relative intersection. (Contributed by Mario Carneiro, 30-Dec-2016)

Ref Expression
Assertion elriin ( 𝐵 ∈ ( 𝐴 𝑥𝑋 𝑆 ) ↔ ( 𝐵𝐴 ∧ ∀ 𝑥𝑋 𝐵𝑆 ) )

Proof

Step Hyp Ref Expression
1 elin ( 𝐵 ∈ ( 𝐴 𝑥𝑋 𝑆 ) ↔ ( 𝐵𝐴𝐵 𝑥𝑋 𝑆 ) )
2 eliin ( 𝐵𝐴 → ( 𝐵 𝑥𝑋 𝑆 ↔ ∀ 𝑥𝑋 𝐵𝑆 ) )
3 2 pm5.32i ( ( 𝐵𝐴𝐵 𝑥𝑋 𝑆 ) ↔ ( 𝐵𝐴 ∧ ∀ 𝑥𝑋 𝐵𝑆 ) )
4 1 3 bitri ( 𝐵 ∈ ( 𝐴 𝑥𝑋 𝑆 ) ↔ ( 𝐵𝐴 ∧ ∀ 𝑥𝑋 𝐵𝑆 ) )