Metamath Proof Explorer


Theorem ovif2

Description: Move a conditional outside of an operation. (Contributed by Thierry Arnoux, 1-Oct-2018)

Ref Expression
Assertion ovif2
|- ( A F if ( ph , B , C ) ) = if ( ph , ( A F B ) , ( A F C ) )

Proof

Step Hyp Ref Expression
1 oveq2
 |-  ( if ( ph , B , C ) = B -> ( A F if ( ph , B , C ) ) = ( A F B ) )
2 oveq2
 |-  ( if ( ph , B , C ) = C -> ( A F if ( ph , B , C ) ) = ( A F C ) )
3 1 2 ifsb
 |-  ( A F if ( ph , B , C ) ) = if ( ph , ( A F B ) , ( A F C ) )