We prove three results on the a-points of the derivatives of the Riemann zeta function. The first result is a formula of the Riemann-von Mangoldt type; we estimate the number of the a-points of the derivatives of the Riemann zeta function. The second result is on certain exponential sum involving a-points. The third result is an analogue of the zero density theorem. We count the a-points of the derivatives of the Riemann zeta function in 1/2 − (log log T ) 2 / log T < ℜs < 1/2 + (log log T ) 2 / log T .
IntroductionThe Riemann zeta function ζ(s) is one of the most important functions in number theory, and its importance comes from its relation to the distribution of primes.The theory of the Riemann zeta function has a famous conjecture, which is the Riemann hypothesis. The Riemann hypothesis states that all of the nontrivial zeros of the Riemann zeta function are located on the critical line, ℜs = 1/2.Hence it is important to study the zeros of the Riemann zeta function. In 1905, von Mangoldt proved the Riemann-von Mangoldt formulawhere N (T ) is the number of zeros of the Riemann zeta function counted with multiplicity in the region 0 < ℑs < T . As a generalization of this formula, in 1913, Landau [3] estimated the number of the a-points of the Riemann zeta function, where we define the a-point of the function f (s) as a root of f (s) = a. Especially, ρ a = β a + iγ a denotes the a-points of ζ(s). For a ∈ C, he proved the following;(1.1) 1 a-points of ζ (k) (s)