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Nobushige Kurokawa

Publications and source records attributed to Nobushige Kurokawa.

At least 19 recordsLinked to original sources
arXiv2023

Towards the Deep Riemann Hypothesis for $\mathrm{GL}_{n}$

We explicate the deep Riemann hypothesis for the general linear group $\mathrm{GL}_{n}$ on the convergence of normalised Euler products of standard $L$-functions on the critical line. It conditionally improves upon the error term in the prime number theorem beyond what the grand Riemann hypothesis predicts. Furthermore, we discuss the Chebyshev bias for Satake parameters on $\mathrm{GL}_{n}$ from the perspective of the deep Riemann hypothesis.

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arXiv2022

Transcendency of the determinant of the Riemann operator: on higher $K$-groups

In previous papers we investigated basic properties of the determinant $G_{K}(s)$ of the Riemann operator: ${\mathcal R}$ acting on $\bigoplus_{n>1} K_{n}(A)_{\mathbb{C}}$, where $A$ is the integer ring of an algebraic number field $K$. The function $G_{K}(s)$ is defined as the regularized determinant \[ G_{K}(s) = {\rm det} ((s I-\mathcal{R}) | \bigoplus_{n>1} K_{n}(A)_{\mathbb{C}} ) \] with $\mathcal{R} | K_{n}(A)_{\mathbb{C}} = \frac{1-n}{2}$. We showed that $G_{K}(s)^{-1}$ is essentially the so called gamma factors of Dedekind zeta function of $K$. In this paper we study the transcendency of $G_{K}(s)$ for some rational numbers $s$. The result depends on types of $K$. For example, we show that $G_{K}(\frac{1}{3})$ is a transcendental number if $K$ is a totally imaginary and $G_{K}(\frac{1}{2})$ is a transcendental number otherwise.

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arXiv2022

Determinants of Riemann operators on Quillen's higher $K$-groups: periodicity

In a previous paper [KT] we introduced determinant of the Riemann operator on Quillen's higher $K$-groups of the integer ring of an algebraic number field $K$. We showed that the determinant expresses essentially the inverse of the so called gamma factor of Dedekind zeta function of $K$. Here we study the periodicity of determinant. This comes from the famous "periodicity" of higher $K$ groups. This periodicity is analogous to Euler's periodicity of gamma function $Γ(x+1)=xΓ(x)$. We investigate the "reflection formula" corresponding to Euler's reflection formula $Γ(x)Γ(1-x)=\fracπ{\sin(πx)}$ also.

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arXiv2022

Riemann operators on higher $K$-groups

We introduce Riemann operators acting on Quillen's higher $K$--groups $K_{n}(A)$ for the integer ring $A$ of an algebraic number field $K$. Especially we prove that gamma factors of Dedekind zeta function of $K$ are obtained as regularized determinants of Riemann operators.

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arXiv2022

Variations on theorems of Mertens

We present variations on theorems of Mertens as special cases of Density Hypothesis. Moreover, we study a Serre's estimate concerning Lang-Weil estimate.

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arXiv2017

Counting and zeta functions over F1

A new interpretation of zeta functions is given for F1-schemes which do not satisfy Soulé's condition. Functional equations for reductive groups are computed and a new definition of zeta functions attached to more general counting functions is given which is based on regularization and puts on an equal footing F1-theory on the one hand and spectral theory of Laplace operators on manifolds on the other.

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arXiv2015

Triple mean values of Witten $L$-functions

Mean values of Witten $L$-functions in the "character" aspect are investigated. After giving a general formula for mean values with the first and the second power, we explicitly calculate the cubic moment for $SU(2)$.

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arXiv2013

Euler Products beyond the Boundary

We investigate the behavior of the Euler products of the Riemann zeta function and Dirichlet L-functions on the critical line. A refined version of the Riemann hypothesis, which is named "the Deep Riemann Hypothesis" (DRH), is examined. We also study various analogs for global function fields. We give an interpretation for the nontrivial zeros from the viewpoint of statistical mechanics.

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arXiv2013

Zeros of Witten zeta functions and absolute limit

We introduce multiple versions of L-functions for Witten zeta functions. We study their algebraic and analytic properties. Especially we investigate the existence of zeros at negative integers. These results strongly suggest the universal zero at -2. We look at their absolute limits also.

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arXiv2013

Dualities for absolute zeta functions and multiple gamma functions

We study absolute zeta functions from the view point of a canonical normalization. We introduce the absolute Hurwitz zeta function for the normalization. In particular, we show that the theory of multiple gamma and sine functions gives good normalizations in cases related to the Kurokawa tensor product. In these cases, the functional equation of the absolute zeta function turns out to be equivalent to the simplicity of the associated non-classical multiple sine function of negative degree.

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arXiv2011

Milnor-Selberg zeta functions and zeta regularizations

By a similar idea for the construction of Milnor's gamma functions, we introduce "higher depth determinants" of the Laplacian on a compact Riemann surface of genus greater than one. We prove that, as a generalization of the determinant expression of the Selberg zeta function, this higher depth determinant can be expressed as a product of multiple gamma functions and what we call a Milnor-Selberg zeta function. It is shown that the Milnor-Selberg zeta function admits an analytic continuation, a functional equation and, remarkably, has an Euler product.

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arXiv2009

Higher Mahler measures and zeta functions

We consider a generalization of the Mahler measure of a multivariable polynomial $P$ as the integral of $\log^k|P|$ in the unit torus, as opposed to the classical definition with the integral of $\log|P|$. A zeta Mahler measure, involving the integral of $|P|^s$, is also considered. Specific examples are computed, yielding special values of zeta functions, Dirichlet $L$-functions, and polylogarithms.

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