let K be Field; :: thesis: for x, y being FinSequence of
for a being Element of st len x = len y holds
|((a * x),y)| = a * |(x,y)|
let x, y be FinSequence of ; :: thesis: for a being Element of st len x = len y holds
|((a * x),y)| = a * |(x,y)|
let a be Element of ; :: thesis: ( len x = len y implies |((a * x),y)| = a * |(x,y)| )
assume len x = len y ; :: thesis: |((a * x),y)| = a * |(x,y)|
then Sum (mlt (a * x),y) = Sum (a * (mlt x,y)) by Th8;
then Sum (mlt (a * x),y) = a * (Sum (mlt x,y)) by FVSUM_1:92;
then Sum (mlt (a * x),y) = a * |(x,y)| by FVSUM_1:def 10;
hence |((a * x),y)| = a * |(x,y)| by FVSUM_1:def 10; :: thesis: verum