Jiro Sekiguchi

ORCID: 0000-0002-9418-2102
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Research Areas
  • Advanced Algebra and Geometry
  • Algebraic Geometry and Number Theory
  • Advanced Topics in Algebra
  • Finite Group Theory Research
  • Nonlinear Waves and Solitons
  • Polynomial and algebraic computation
  • Advanced Differential Equations and Dynamical Systems
  • Mathematics and Applications
  • Advanced Combinatorial Mathematics
  • graph theory and CDMA systems
  • Geometric and Algebraic Topology
  • Algebraic structures and combinatorial models
  • Geometric Analysis and Curvature Flows
  • advanced mathematical theories
  • Geometry and complex manifolds
  • Coding theory and cryptography
  • Differential Equations and Boundary Problems
  • Commutative Algebra and Its Applications
  • Homotopy and Cohomology in Algebraic Topology
  • Matrix Theory and Algorithms
  • Differential Equations and Numerical Methods
  • Advanced Mathematical Identities
  • Horticultural and Viticultural Research
  • Analytic and geometric function theory
  • Advanced Mathematical Modeling in Engineering

Tokyo University of Agriculture and Technology
2004-2022

University of Electro-Communications
1987-2018

Tokyo Metropolitan University
1976-2018

Himeji University
1997

Sophia University
1991

Saitama University
1979-1981

Urawa University
1981

Institute for Advanced Study
1980

Kyoto University
1976

In this paper, we shall study the real nilpotent orbits of vector space associated to a semisimple symmetric pair.Let $\mathfrak{g}$ be Lie algebra and let $\sigma$ its involution.Then obtain direct sum decomposition $\mathfrak{g}=\mathfrak{h}+q$ for .The pair $(\mathfrak{g}, \mathfrak{h})$ is called pair.The first purpose paper prove theorem concerning H-orbital structure subvariety $\mathfrak{N}(q)$ $q$ second determine orbital when split rank one in sense [OS, Def. 2.5.1].We are going...

10.2969/jmsj/03910127 article EN Journal of the Mathematical Society of Japan 1987-01-01

(1980). On a certain generator system of the ring invariants finite reflection group. Communications in Algebra: Vol. 8, No. 4, pp. 373-408.

10.1080/00927878008822464 article EN Communications in Algebra 1980-01-01

10.2969/aspm/00410433 article EN other-oa Advanced studies in pure mathematics 2018-06-06

Let G be a real semisimple Lie group with finite center, and K maximal compact subgroup of G. A zonal spherical function on the symmetric space X=G/K is an simulatneous eigeiifunction (p(x) all invariant differential operators X satisfying (p(kx) = cp(x) for any x^X, k^K, (p(eK) =1, where e identity element in By Cartan decomposition KAK, considered as A. And by separation variables, we obtain from operators, which are called their radial components. In this paper, investigate components...

10.2977/prims/1195196620 article EN Publications of the Research Institute for Mathematical Sciences 1976-12-31

Flat structure was introduced by K. Saito and his collaborators at the end of 1970's. Independently WDVV equation arose from 2D topological field theory. B. Dubrovin unified these two notions as Frobenius manifold structure. In this paper, we study isomonodromic deformations an Okubo system, which is a special kind systems linear differential equations. We show that space independent variables such can be equipped with (without metric), C. Sabbah generalization manifold. As its consequence,...

10.3842/sigma.2020.110 article EN cc-by-sa Symmetry Integrability and Geometry Methods and Applications 2020-11-03

10.2977/prims/1195181836 article EN Publications of the Research Institute for Mathematical Sciences 1984-02-29

Ever since S. Helgason [4] showed that any eigenfunction of the Laplace-Beltrami operator on unit disk is represented by Poisson integral a hyperfunction circle, much interest has been arisen to study representation joint eigenfunctions all invariant differential operators symmetric space X. In particular, his original idea expanding into K -finite functions proved be generalizable up case where X Riemannian rank one (cf. [4], [5], [11]). Presently, extension arbitrary completed quite...

10.1017/s0027763000019000 article EN Nagoya Mathematical Journal 1980-10-01

10.2969/aspm/00610083 article EN Advanced studies in pure mathematics 2018-06-06

For the notation, see [9].Let $X$ be an l-dimensional complex mani- fold and let $T^{*}X$ cotangent bundle over .Let, further, $\pi$ denote projection of to .A holonomic system $\mathscr{L}$ is then a coherent $\mathcal{D}_{X}$ -Module with $co\dim_{TX}SS(\mathscr{L})=l\vee$ .An irreducible component $ SS(\mathscr{L})\vee$ called variety.The holonomy diagram determined as follows.To each variety $\Lambda$ corresponds circle inscribing .The \copyright -\copyright means that two varieties...

10.3836/tjm/1270215738 article EN Tokyo Journal of Mathematics 1981-06-01

We describe an approach to classification of weighted homogeneous Saito free divisors in C 3 . This is mainly based on properties Lie algebras vector fields tangent reduced hypersurfaces at their non-singular points. In fact we also obtain a such having similar as ones for discriminants associated with irreducible real reflection groups rank 3. Among other things briefly discuss some applications the theory 3, interesting relationships root systems types E 6 , 7 8 and few examples higher...

10.2969/jmsj/06141071 article EN Journal of the Mathematical Society of Japan 2009-10-01

10.2206/kyushujm.48.123 article EN Kyushu Journal of Mathematics 1994-01-01

leave $f(x)=f_{W}(x)$ invariant.More precisely, we havewith certain polynomials $c_{i}(x)\in R$ .Furthermore, $X_{1},$ $\cdots,$ $X_{l}$ form a free basis of the Lie algebra vector fields leaving set $\{x;f(x)=0\}$ invariant ([7]).In this paper, shall study microlocal structure $\mathcal{D}_{X}$ -Module

10.3836/tjm/1270216319 article EN Tokyo Journal of Mathematics 1979-12-01

Let l1,l2,...,l7 be mutually different seven lines on the real projective plane. We consider two conditions;(A) No three of intersect at a point. (B) There is no conic tangent to any six l1,l2, . , l7. Cummings [3] and White [16] showed that there are eleven non-equivalent classes systems with condition (A)(cf. [7], Chap. 18). The purposes this article give an interpretation classification in terms root system type E7. To accomplish this, it better add for lines. Moreover we need notion...

10.2969/jmsj/05140987 article EN Journal of the Mathematical Society of Japan 1999-10-01

Let ${\mathcal O}$ be a nilpotent orbit in $\mathfrak{so}(p,q)$ under the adjoint action of full orthogonal group ${\rm O}(p,q)$. Then closure (with respect to Euclidean topology) is union and some O}(p,q)$-orbits smaller dimensions. In an earlier work, first author has determined which belong this closure. The same problem for identity component SO}(p,q)^0$ O}(p,q)$ on much harder we propose conjecture describing closures SO}(p,q)^0$-orbits. proved when $\min(p,q)\le7$. Our method indirect...

10.2748/tmj/1178207418 article EN Tohoku Mathematical Journal 2001-01-01

0. Introduction.Let g0 be a real semisimple Lie algebra and let 0+0 Cartan decomposition of go.We complexify 0, 0 P0 denote them by g, p, respectively.Let G the adjoint group K analytic subgroup corresponding to

10.3792/pjaa.57.42 article EN Proceedings of the Japan Academy Series A Mathematical Sciences 1981-01-01

A tritangent plane., or a for short, means projective plane which meets the surface in union of three lines.Since exactly 5 tritangents pass through each lines upon surface, it follows that famous theorem: There are 27 the.general cubic surface.

10.3792/pjaa.56.122 article EN Proceedings of the Japan Academy Series A Mathematical Sciences 1980-01-01

10.2969/jmsj/04620355 article EN Journal of the Mathematical Society of Japan 1994-01-01

A potential vector field is a solution of an extended WDVV equation which generalization equation.It expected that fields corresponding to algebraic solutions Painlevé VI can be written by using polynomials or functions explicitly.The purpose this paper construct more than thirty non-equivalent solutions.

10.7494/opmath.2018.38.2.201 article EN cc-by-nc Opuscula Mathematica 2017-12-29

<!-- *** Custom HTML --> The aim of this report is to determine the fundamental group an arbitrary irreducible semisimple symmetric space $G/H$ when $G$ a connected Lie with trivial center. $\pi_1(G/H)$ well-known if Riemannian. Therefore, we restrict our attention case where non-Riemannian so both and $H$ are not compact. result summarized in Table 4.

10.2969/aspm/01410519 article EN Advanced studies in pure mathematics 2018-06-06
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