Metamath Proof Explorer


Theorem resdifcom

Description: Commutative law for restriction and difference. (Contributed by AV, 7-Jun-2021)

Ref Expression
Assertion resdifcom
|- ( ( A |` B ) \ C ) = ( ( A \ C ) |` B )

Proof

Step Hyp Ref Expression
1 indif1
 |-  ( ( A \ C ) i^i ( B X. _V ) ) = ( ( A i^i ( B X. _V ) ) \ C )
2 df-res
 |-  ( ( A \ C ) |` B ) = ( ( A \ C ) i^i ( B X. _V ) )
3 df-res
 |-  ( A |` B ) = ( A i^i ( B X. _V ) )
4 3 difeq1i
 |-  ( ( A |` B ) \ C ) = ( ( A i^i ( B X. _V ) ) \ C )
5 1 2 4 3eqtr4ri
 |-  ( ( A |` B ) \ C ) = ( ( A \ C ) |` B )