let K be Field; for x being FinSequence of K holds |(x,(0* (K,(len x))))| = 0. K
let x be FinSequence of K; |(x,(0* (K,(len x))))| = 0. K
set n = len x;
reconsider p1 = x as Element of (len x) -tuples_on the carrier of K by FINSEQ_2:92;
|(x,(0* (K,(len x))))| =
Sum (mlt (p1,(0* (K,(len x)))))
by FVSUM_1:def 9
.=
Sum (0* (K,(len x)))
by Th13
.=
0. K
by MATRIX_3:11
;
hence
|(x,(0* (K,(len x))))| = 0. K
; verum