On distribution of zeros for a class of meromorphic functions
Yu. F. Korobeĭnik Southern Mathematical Institute of the Vladikavkaz Scientific Center of the Russian Academy of Sciences, Vladikavkaz
Abstract:
In this article some class
$\mathcal{K}_0$ of meromorphic functions
is introduced. Each function
$y(z)$ from
$\mathcal{K}_0$
satisfies the functional equation
$y(z)=b_y(z)y(1-z)$ with its own «Riemann's multiplier»
$b_y(z)$ which is a meromorphic function with real zeros and poles.
All poles of an arbitrary function from
$\mathcal{K}_0$ are real and
belong to the interval
$(\frac12,\frac12+h_1]$,
$h_1=h_1(y)$.
Using the theory of residues we prove some relation
connecting the following magnitudes:
$\mathcal{P}_y$, the
sum of all orders of poles of
$y \in \mathcal{K}_0$;
$\mathcal{N}_y(T)$, the sum of multiplicities of all zeros of
$y$
having the form
$\frac12 +i\tau$,
$|\tau|<T$;
$\mathcal{N}_y(T,\sigma)$, the sum of multiplicities of all zeros
of
$y$ which lies inside the rectangle with vertices
$A=\frac12-\sigma - iT$,
$C=\frac12+\sigma - iT$,
$D=\frac12+\sigma
+ iT$,
$F=\frac12-\sigma + iT$. Here
$T$ is a
$y$-regular ordinate,
that is,
$y(z)$ is analytic and has no zeros on the line
$\operatorname{Im} z =T$,
$\operatorname{Re} z \in \mathbb{R}$,
$\sigma\in (h_1,h)$,
$h=h(y)$,
$\sigma$ is chosen in such a manner
that
$y(z)\ne 0$ on the segments
$[F,A]$ and
$[C,D]$.
The problem of finding the magnitudes of
$\mathcal{P}_y$,
$\mathcal{N}_y(T)$ and
$\mathcal{N}_y(T,\sigma)$
with the help of corresponding characteristics of the «Riemann's
multiplier»
$b_y(z)$ is posed. This problem is solved in the paper for
$\mathcal{P}_y$.
Moreover, the obtained equality enables one to deduce a
definite relation the left part of which contains the number
$2\alpha_{T_0}+ 4\beta_{T_0}$ where
$T_0$ is arbitrary
$y$-nonregular ordinate,
$\alpha_{T_0}$ is the multiplicities of all
possible zero of
$y$ of the form
$\frac12+iT_0$,
$\beta_{T_0}$ is
the sum of multiplicities of all possible zeros of
$y$ belonging to
$\frac12+iT_0,+\infty +iT_0$.
It is proved that the class
$\mathcal{K}_0$ contains the Riemann's
Zeta-Function.
Key words:
zeros of meromorphic functions, functional equation.
UDC:
517.547.2 Received: 23.10.2016