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Kohji Matsumoto

Publications and source records attributed to Kohji Matsumoto.

At least 37 records · Page 2Linked to original sources
arXiv2020

Expressions of Schur multiple zeta-functions of anti-hook type by zeta-functions of root systems

We investigate relations among Schur multiple zeta functions and zeta-functions of root systems attached to semisimple Lie algebras. Schur multiple zeta functions are defined as sums over semi-standard Young tableaux. Then, assuming the Young tableaux is of anti-hook shape, we show that they can be written in terms of modified zeta-functions of root systems of type $A$. Our proof is quite computational, but we also give a pictorial interpretation of our argument in terms of Young tableaux. It is also possible to understand that one of our theorems gives an expression of Schur multiple zeta functions by an analogue of Weyl group multiple Dirichlet series in the sense of Bump et al. By combining with a result of Nakasuji, Phuksuwan and Yamasaki, our theorems yield a new method of finding functional relations among zeta-functions of root systems.

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arXiv2020

An asymptotic formula for the $2k$-th power mean value of $\left| (L'/L)(1+it_0, χ)\right|$

Let $q$ be a positive integer ($\geq 2$), $χ$ be a Dirichlet character modulo $q$, $L(s, χ)$ be the attached Dirichlet $L$-function, and let $L^\prime(s, χ)$ denote its derivative with respect to the complex variable $s$. Let $t_0$ be any fixed real number. The main purpose of this paper is to give an asymptotic formula for the $2k$-th power mean value of $\left|(L^\prime/L)(1+it_0, χ)\right|$ when $χ$ runs over all Dirichlet characters modulo $q$ (except the principal character when $t_0=0$).

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arXiv2019

Values of multiple zeta-functions with polynomial denominators at non-positive integers

We study rather general multiple zeta-functions whose denominators are given by polynomials. The main aim is to prove explicit formulas for the values of those multiple zeta-functions at non-positive integer points. We first treat the case when the polynomials are power sums, and observe that some ``trivial zeros'' exist. We also prove that special values are sometimes transcendental. Then we proceed to the general case, and show an explicit expression of special values at non-positive integer points which involves certain period integrals. We give examples of transcendental values of those special values or period integrals. We also mention certain relations among Bernoulli numbers which can be deduced from our explicit formulas. Our proof of explicit formulas are based on the Euler-Maclaurin summation formula, Mahler's theorem, and a Raabe-type lemma due to Friedman and Pereira.

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arXiv2019

On mixed joint discrete universality for a class of zeta-functions III

We present the most general at this moment results on the discrete mixed joint value-distribution and the universality property for the class of Matsumoto zeta-functions and periodic Hurwitz zeta-functions under certain linear independence condition on the relevant parameters, such as common differences of arithmetic progressions, prime numbers etc.

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arXiv2019

Numerical computations on the zeros of the Euler double zeta-function II

We study the behavior of zero-divisors of the double zeta-function $ζ_2(s_1,s_2)$. In our former paper \cite{MatSho14} we studied the case $s_1=s_2$, but in the present paper we consider the more general two variable situation. We carry out numerical computations in order to trace the behavior of zero-divisors. We observe that some divisors approach the points with $s_2=0$, while other divisors approach the points which are solutions of $ζ(s_2)=1$.

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arXiv2018

Values at non-positive integers of generalized Euler-Zagier multiple zeta-functions

We give new closed and explicit formulas for "multiple zeta values" at non-positive integers of generalized Euler-Zagier multiple zeta-functions. We first prove these formulas for a small convenient class of these multiple zeta-functions and then use the analyticity of the values on the parameters defining the multiple zeta-functions to deduce the formulas in the general case. Also, for our aim we prove an extension of "Raabe's lemma" due to E. Friedman and A. Pereira.

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arXiv2018

An overview and supplements to the theory of functional relations for zeta-functions of root systems

We give an overview of the theory of functional relations for zeta-functions of root systems, and show some new results on functional relations involving zeta-functions of root systems of types $B_r$, $D_r$, $A_3$ and $C_2$. To show those new results, we use two different methods. The first method, for $B_r$, $D_r$, $A_3$, is via generating functions, which is based on the symmetry with respect to Weyl groups, or more generally, on our theory of lattice sums of certain hyperplane arrangements. The second method for $C_2$ is more elementary, using partial fraction decompositions.

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arXiv2018

Double Dirichlet series associated with arithmetic functions

We consider double Dirichlet series associated with arithmetic functions such as the von Mangoldt function, the Möbius function, and so on. We show analytic continuations of them by use of the Mellin-Barnes integral. Furthermore we observe their reverse values at non-positive integer points.

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arXiv2018

On the theory of $M$-functions

We survey the value-distribution theory of zeta and $L$-functions, originated by H. Bohr, and developed further by Y. Ihara and others recently.

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arXiv2018

On mixed joint discrete universality for a class of zeta-functions II

We study analytic properties of the pair consisting of a rather general form of zeta-function with an Euler product and a periodic Hurwitz zeta-function with a transcendental parameter. We first survey briefly previous results, and then investigate the mixed joint discrete value distribution and prove the mixed joint discrete universality theorem for these functions, in the case when common differences of relevant arithmetic progressions are not necessarily the same. Also some generalizations are given. For this purpose, certain arithmetic conditions on the common differences are necessary.

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arXiv2018

On the value-distribution of symmetric power L-functions

We first briefly survey the value-distribution theory of L-functions of the Bohr-Jessen flavor (or the theory of "M-functions"). Limit formulas for the Riemann zeta-function, Dirichlet L-functions, automorphic L-functions etc. are discussed. Then we prove new results on the value-distribution of symmetric power L-functions, which are limit formulas involving associated M-functions.

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arXiv2018

The discrete case of the mixed joint universality for a class of certain partial zeta-functions

We give a new type of mixed discrete joint universality properties, which is satisfied by a wide class of zeta-functions. We study the universality for a certain modification of a Matsumoto zeta-function and a periodic Hurwitz zeta-function under certain arithmetic condition on the common difference of arithmetical progression and the shifting parameter. Also we generalize a known discrete universality result in our former paper and the new one as well.

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arXiv2017

Goldbach Representations in Arithmetic Progressions and zeros of Dirichlet L-functions

Assuming a conjecture on distinct zeros of Dirichlet L-functions we get asymptotic results on the average number of representations of an integer as the sum of two primes in arithmetic progression. On the other hand the existence of good error terms gives information on the the location of zeros of L-functions and possible Siegel zeros. Similar results are obtained for an integer in a congruence class expressed as the sum of two primes.

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arXiv2017

Zeta-functions of root systems and Poincaré polynomials of Weyl groups

We consider a certain linear combination $S(\mathbf{s},\mathbf{y};I;Δ)$ of zeta-functions of root systems, where $Δ$ is a root system of rank $r$ and $I\subset\{1,2,\ldots,r\}$. Showing two different expressions of $S(\mathbf{s},\mathbf{y};I;Δ)$, we find that a certain signed sum of zeta-functions of root systems is equal to a sum involving Bernoulli functions of root systems. This identity gives a non-trivial functional relation among zeta-functions of root systems, if the signed sum does not identically vanish. This is a genralization of the authors' previous result proved in \cite{KMTLondon}, in the case when $I=\emptyset$. We present several explicit examples of such functional relations. A criterion of the non-vanishing of the signed sum, in terms of Poincar{é} polynomials of associated Weyl groups, is given. Moreover we prove a certain converse theorem, which implies that the generating function for the case $I=\emptyset$ essentially knows all information on generating functions for general $I$.

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arXiv2017

On the density function for the value-distribution of automorphic $L$-functions

The Bohr-Jessen limit theorem is a probabilistic limit theorem on the value-distribution of the Riemann zeta-function in the critical strip. Moreover their limit measure can be written as an integral involving a certaindensity function. The existence of the limit measure is now known for a quite general class of zeta-functions, but the integral expression has been proved only for some special cases (such as Dedekind zeta-functions). In this paper we give an alternative proof of the existence of the limit measure for a general setting, and then prove the integral expression, with an explicitly constructed density function, for the case of automorphic L-functions attached to primitive forms with respect to congruence subgroups Gamma_0(N).

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arXiv2016

On mixed joint discrete universality for a class of zeta-functions

We prove a mixed joint discrete universality theorem for a Matsumoto zeta-function $φ(s)$ (belonging to the Steuding subclass) and a periodic Hurwitz zeta-function $ζ(s,α;{\mathfrak{B}})$. For this purpose, certain independence condition for the parameter $α$ and the minimal step of discrete shifts of these functions is assumed. This paper is a continuation of authors' works [12] and [arXiv:1601.03795].

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arXiv2016

Remarks on the mixed joint universality for a class of zeta-functions

Two remarks related with the mixed joint universality for a polynomial Euler product and a periodic Hurwitz zeta-function with a transcendental parameter are given. One is the mixed joint functional independence, and the other is a generalized universality, which includes several periodic Hurwitz zeta-functions.

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