Tetsuji Taniguchi

J-GLOBAL         Last updated: Oct 16, 2015 at 18:17
 
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Name
Tetsuji Taniguchi
Affiliation
Hiroshima Institute of Technology
Job title
Assistant Professor
Degree
Ph. D (Mathematics, Kyushu Univ.)

Research Areas

 
 

Academic & Professional Experience

 
Sep 2014
 - 
Today
Associate Professor, Department of Electronics and Computer Engineering, Hiroshima Institute of Technology
 
Dec 2008
 - 
Today
Assistant Professor, Matsue College of Technology
 
Apr 1998
 - 
Nov 2008
Kyushu univ.
 

Published Papers

 
Akihiro Munemasa, Yoshio Sano, Tetsuji Taniguchi
Linear Algebra and Its Applications   466 501-511   Feb 2015   [Refereed]
© 2014 Elsevier Inc. Allrights reserved. In this paper, we study the characteristic polynomials of the line graphs of generalized Bethe trees. We give an infinite family of such graphs sharing the same smallest eigenvalue. Our family generalizes t...
Gary Greaves, Jack Koolen, Akihiro Munemasa, Yoshio Sano, Tetsuji Taniguchi
Journal of Combinatorial Theory. Series B   110 90-111   Jan 2015   [Refereed]
© 2014 Elsevier Inc. We give a structural classification of edge-signed graphs with smallest eigenvalue greater than -2. We prove a conjecture of Hoffman about the smallest eigenvalue of the line graph of a tree that was stated in the 1970s. Furth...
Hye Jin Jang, Jack Koolen, Akihiro Munemasa, Tetsuji Taniguchi
Ars Mathematica Contemporanea   7(1) 105-121   Jan 2014   [Refereed]
We investigate fat Hoffman graphs with smallest eigenvalue at least -3, using their special graphs. We show that the special graph S(H) of an indecomposable fat Hoffman graph H is represented by the standard lattice or an irreducible root lattice....
Akihiro Munemasa, Yoshio Sano, Tetsuji Taniguchi
Ars Mathematica Contemporanea   7(1) 247-262   Jan 2014   [Refereed]
In this paper, we show that all fat Hoffman graphs with smallest eigenvalue at least 1-τ, where τ is the golden ratio, can be described by a finite set of fat (-1 - τ )-irreducible Hoffman graphs. In the terminology of Woo and Neumaier, we mean th...
Akihiro Munemasa, Yoshio Sano, Tetsuji Taniguchi
Discrete Applied Mathematics   176 78-88   2014   [Refereed]
Michio Seto, Sho Suda, Tetsuji Taniguchi
Linear algebra and its applications   445 56-68   2014   [Refereed]
Tetsuji Taniguchi
Ars Mathematica Contemporanea   5(2) 243-258   Jun 2012   [Refereed]
This is a continuation of the article with the same title. In this paper, the family H is the same as in the previous paper [11]. The main result is that a minimal graph which is not an H-line graph, is just isomorphic to one of the 38 graphs foun...
T. Taniguchi, T. Chung, J. Koolen, Y. Sano
Linear Algebra and its Applications   435(10) 2544-2559   Nov 2011   [Refereed]
In this paper, we classify the connected non-bipartite integral graphs with spectral radius three.
On graphs with the smallest eigenvalue at least Tex, part I
T. Taniguchi
ARS MATHEMATICA CONTEMPORANEA   1(1) 81-98   Aug 2008   [Refereed]
There are many results on graphs with the smallest eigenvalue at least Tex.
As a next step, A. J. Hoffman proposed to study graphs with the smallest eigenvalue at least Tex. In order to deal with such graphs, R. Woo and A. Neumaier intr...
The smallest eigenvalues of the line graphs of some trees -- Cvetković and Stevanović's Question --
Tetsuji Taniguchi

Misc

 
Gary Greaves, Jack Koolen, Akihiro Munemasa, Yoshio Sano, Tetsuji Taniguchi
   Sep 2013
We give a structural classification of edge-signed graphs with smallest
eigenvalue greater than -2. We prove a conjecture of Hoffman about the smallest
eigenvalue of the line graph of a tree that was stated in the 1970s.
Furthermore, we prove a mo...

Conference Activities & Talks

 
A representation of Hoffman graphs
Tetsuji Taniguchi
Systems of Lines: Applications of Algebraic Combinatorics   12 Aug 2015   
Hoffman graphs with the smallest eigenvalue at least −3
Tetsuji Taniguchi
8th Slovenian Conference on Graph Theory, Kranjska Gora   21 Jun 2015   
Hoffman graphs with the smallest eigenvalue at least Tex
Tetsuji Taniguchi
13 Dec 2014   
The smallest eigenvalues of the line graphs of some trees -- Cvetković and Stevanović’s Question --
Tetsuji Taniguchi
20 Aug 2014   
The smallest eigenvalues of the line graphs of some trees -- Cvetković and Stevanović’s Question --
Tetsuji Taniguchi
19 Jun 2014   
Hoffman graphs and a hierarchical structure of graphs
Tetsuji Taniguchi
Combinatorics Summer school 2013 (COS 2013)   3 Sep 2013   
Hoffman graphs and edge-signed graphs
Tetsuji Taniguchi
The 30th Algebraic Combinatorics Symposium   26 Jun 2013   
On the smallest eigenvalue of graphs and Hoffman graphs [Invited]
Tetsuji Taniguchi
Workshop of Quantum Dynamics and Quantum Walks   24 Nov 2012   
On fat Hoffman graphs with smallest eigenvalue at least −3 [Invited]
Tetsuji Taniguchi
日本数学会・秋季総合分科会(応用数学)   18 Sep 2012   
On fat Hoffman graphs with smallest eigenvalue greater than Tex
Tetsuji Taniguchi
2012 Shanghai Conference on Algebraic Combinatorics   19 Aug 2012