Metamath Proof Explorer


Theorem fvmpt2d

Description: Deduction version of fvmpt2 . (Contributed by Thierry Arnoux, 8-Dec-2016)

Ref Expression
Hypotheses fvmpt2d.1
|- ( ph -> F = ( x e. A |-> B ) )
fvmpt2d.4
|- ( ( ph /\ x e. A ) -> B e. V )
Assertion fvmpt2d
|- ( ( ph /\ x e. A ) -> ( F ` x ) = B )

Proof

Step Hyp Ref Expression
1 fvmpt2d.1
 |-  ( ph -> F = ( x e. A |-> B ) )
2 fvmpt2d.4
 |-  ( ( ph /\ x e. A ) -> B e. V )
3 1 fveq1d
 |-  ( ph -> ( F ` x ) = ( ( x e. A |-> B ) ` x ) )
4 3 adantr
 |-  ( ( ph /\ x e. A ) -> ( F ` x ) = ( ( x e. A |-> B ) ` x ) )
5 id
 |-  ( x e. A -> x e. A )
6 eqid
 |-  ( x e. A |-> B ) = ( x e. A |-> B )
7 6 fvmpt2
 |-  ( ( x e. A /\ B e. V ) -> ( ( x e. A |-> B ) ` x ) = B )
8 5 2 7 syl2an2
 |-  ( ( ph /\ x e. A ) -> ( ( x e. A |-> B ) ` x ) = B )
9 4 8 eqtrd
 |-  ( ( ph /\ x e. A ) -> ( F ` x ) = B )