Metamath Proof Explorer


Theorem elin2

Description: Membership in a class defined as an intersection. (Contributed by Stefan O'Rear, 29-Mar-2015)

Ref Expression
Hypothesis elin2.x
|- X = ( B i^i C )
Assertion elin2
|- ( A e. X <-> ( A e. B /\ A e. C ) )

Proof

Step Hyp Ref Expression
1 elin2.x
 |-  X = ( B i^i C )
2 1 eleq2i
 |-  ( A e. X <-> A e. ( B i^i C ) )
3 elin
 |-  ( A e. ( B i^i C ) <-> ( A e. B /\ A e. C ) )
4 2 3 bitri
 |-  ( A e. X <-> ( A e. B /\ A e. C ) )