It is easy to see that if the equality τ1αn
1 +···+τdαn
d = 0 holds for all integer
n ≥ n0 then, by taking d consecutive values of n, we must have τ1 = ··· =
τd = 0. Hence, from (2.5), v1 = ξ(αt
1 − 1) − F(α1) and v2 = −F(α2),...,vd =
−F(αd). Inserting this into (2.4), we obtain