We shall consider linear independence measures for the values of the functions
Da(
z) and
Ea(
z) given below, which can be regarded as
q-analogues of Euler's divergent series and the usual exponential series. For the
q-exponential function
Eq(
z), our main result (Theorem 1) asserts the linear independence (over any number field) of the values 1 and
Eq(α
z) (
j = 1,…,
m) together with its measure having the exponent μ =
O (
m), which sharpens the known exponent μ =
O (
m2) obtained by a certain refined version of Siegel's lemma (cf. [
1]). Let
p be a prime number. Then Theorem 1 further implies the linear independence of the
p-adic numbers ∏
n=1∞ (1+
kpn), (
k = 0,1,…,
p-1), over
Q with its measure having the exponent μ < 2
p. Our proof is based on a modification of Maier's method which allows to construct explicit Padé type approximations (of the second kind) for certain
q-hypergeometric series.
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