Metamath Proof Explorer


Theorem resindir

Description: Class restriction distributes over intersection. (Contributed by NM, 18-Dec-2008)

Ref Expression
Assertion resindir
|- ( ( A i^i B ) |` C ) = ( ( A |` C ) i^i ( B |` C ) )

Proof

Step Hyp Ref Expression
1 inindir
 |-  ( ( A i^i B ) i^i ( C X. _V ) ) = ( ( A i^i ( C X. _V ) ) i^i ( B i^i ( C X. _V ) ) )
2 df-res
 |-  ( ( A i^i B ) |` C ) = ( ( A i^i B ) i^i ( C X. _V ) )
3 df-res
 |-  ( A |` C ) = ( A i^i ( C X. _V ) )
4 df-res
 |-  ( B |` C ) = ( B i^i ( C X. _V ) )
5 3 4 ineq12i
 |-  ( ( A |` C ) i^i ( B |` C ) ) = ( ( A i^i ( C X. _V ) ) i^i ( B i^i ( C X. _V ) ) )
6 1 2 5 3eqtr4i
 |-  ( ( A i^i B ) |` C ) = ( ( A |` C ) i^i ( B |` C ) )