EN
Consider the power series $𝔄(z) = ∑_{n=1}^{∞} α(n)zⁿ$, where α(n) is a completely additive function satisfying the condition α(p) = o(lnp) for prime numbers p. Denote by e(l/q) the root of unity $e^{2πil/q}$. We give effective omega-estimates for $𝔄(e(l/p^k)r)$ when r → 1-. From them we deduce that if such a series has non-singular points on the unit circle, then it is a zero function.