Metamath Proof Explorer


Theorem dpval

Description: Define the value of the decimal point operator. See df-dp . (Contributed by David A. Wheeler, 15-May-2015)

Ref Expression
Assertion dpval Could not format assertion : No typesetting found for |- ( ( A e. NN0 /\ B e. RR ) -> ( A . B ) = _ A B ) with typecode |-

Proof

Step Hyp Ref Expression
1 df-dp2 Could not format _ x y = ( x + ( y / ; 1 0 ) ) : No typesetting found for |- _ x y = ( x + ( y / ; 1 0 ) ) with typecode |-
2 oveq1 x = A x + y 10 = A + y 10
3 1 2 eqtrid Could not format ( x = A -> _ x y = ( A + ( y / ; 1 0 ) ) ) : No typesetting found for |- ( x = A -> _ x y = ( A + ( y / ; 1 0 ) ) ) with typecode |-
4 oveq1 y = B y 10 = B 10
5 4 oveq2d y = B A + y 10 = A + B 10
6 df-dp2 Could not format _ A B = ( A + ( B / ; 1 0 ) ) : No typesetting found for |- _ A B = ( A + ( B / ; 1 0 ) ) with typecode |-
7 5 6 eqtr4di Could not format ( y = B -> ( A + ( y / ; 1 0 ) ) = _ A B ) : No typesetting found for |- ( y = B -> ( A + ( y / ; 1 0 ) ) = _ A B ) with typecode |-
8 df-dp Could not format . = ( x e. NN0 , y e. RR |-> _ x y ) : No typesetting found for |- . = ( x e. NN0 , y e. RR |-> _ x y ) with typecode |-
9 6 ovexi Could not format _ A B e. _V : No typesetting found for |- _ A B e. _V with typecode |-
10 3 7 8 9 ovmpo Could not format ( ( A e. NN0 /\ B e. RR ) -> ( A . B ) = _ A B ) : No typesetting found for |- ( ( A e. NN0 /\ B e. RR ) -> ( A . B ) = _ A B ) with typecode |-