let K be Field; for x, y being FinSequence of
for a being Element of st len x = len y holds
( mlt (a * x),y = a * (mlt x,y) & mlt x,(a * y) = a * (mlt x,y) )
let x, y be FinSequence of ; for a being Element of st len x = len y holds
( mlt (a * x),y = a * (mlt x,y) & mlt x,(a * y) = a * (mlt x,y) )
let a be Element of ; ( len x = len y implies ( mlt (a * x),y = a * (mlt x,y) & mlt x,(a * y) = a * (mlt x,y) ) )
assume
len x = len y
; ( mlt (a * x),y = a * (mlt x,y) & mlt x,(a * y) = a * (mlt x,y) )
then reconsider y0 = y as Element of (len x) -tuples_on the carrier of K by Th1;
reconsider x0 = x as Element of (len x) -tuples_on the carrier of K by Th1;
thus mlt (a * x),y =
a * (mlt x0,y0)
by FVSUM_1:83
.=
a * (mlt x,y)
; mlt x,(a * y) = a * (mlt x,y)
thus mlt x,(a * y) =
a * (mlt x0,y0)
by FVSUM_1:83
.=
a * (mlt x,y)
; verum