Description: Membership in a restricted intersection. (Contributed by Stefan O'Rear, 3-Apr-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | elrint2 | ⊢ ( 𝑋 ∈ 𝐴 → ( 𝑋 ∈ ( 𝐴 ∩ ∩ 𝐵 ) ↔ ∀ 𝑦 ∈ 𝐵 𝑋 ∈ 𝑦 ) ) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elrint | ⊢ ( 𝑋 ∈ ( 𝐴 ∩ ∩ 𝐵 ) ↔ ( 𝑋 ∈ 𝐴 ∧ ∀ 𝑦 ∈ 𝐵 𝑋 ∈ 𝑦 ) ) | |
2 | 1 | baib | ⊢ ( 𝑋 ∈ 𝐴 → ( 𝑋 ∈ ( 𝐴 ∩ ∩ 𝐵 ) ↔ ∀ 𝑦 ∈ 𝐵 𝑋 ∈ 𝑦 ) ) |