[Japanese version]
Hiroshi Sekigawa
Professor
Department of Applied Mathematics,
Faculty of Science Division I,
Tokyo University of Science
13 Kagurazaka, Shinjukuku, Tokyo 1628601 Japan
EMail: sekigawaXrs.tus.ac.jp (X = @)
Last modified: July 13, 2017

Tokyo University of Science

Faculty of Science Division I

Department of Applied Mathematics
Research Interests
 Symbolic and Algebraic Computation
 SymbolicNumeric Computation
Biography
1986.3: 
B.S. in mathematics from the University of Tokyo. 
1989.3: 
M.S. in mathematics from the University of Tokyo. 
2004.2: 
Ph.D. in mathematical sciences from the University of Tokyo. 

Ph.D. Thesis: 

Zero Determination of Algebraic Numbers
using Approximate Computation and
its Application to Algorithms in Computer Algebra
[Pdf (271KB)] 
1989.4: Joined Nippon Telegraph and Telephone Corporation (NTT)
1989.5  1994.6:
Research on computeraided design for LSIs
1994.6  2000.3:
Research on symbolic and algebraic computation,
symbolicnumeric computation
2000.4  2002.3: Business Communications Headquarters,
Nippon Telegraph and Telephone West Corporation
2002.4  2010.3: Nippon Telegraph and Telephone Corporation (NTT)
Research on symbolic and algebraic computation,
symbolicnumeric computation
2010.4  2013.3: Tokai University
Research on symbolic and algebraic computation,
symbolicnumeric computation
2013.4  : Tokyo University of Science
Research on symbolic and algebraic computation,
symbolicnumeric computation
Society Membership
Selected Publications
2017

H. Sekigawa,
The Nearest Polynomial to Multiple Given Polynomials with a Given Zero
in the Real Case,
,
Theoretical Computer Science, Vol. 681, pp. 167175,
2017.
2016

Y. Kawano and H. Sekigawa,
Quantum Fourier Transform over Symmetric GroupsImproved Result
,
Journal of Symbolic Computation, Vol. 75, pp. 219243, 2016.
2014

H. Sekigawa,
A Sequence of Nearest Polynomials with Given Factors,
Computer Mathematics: 9th Asian Symposium (ASCM2009), Fukuoka,
December 2009, 10th Asian Symposium (ASCM2012), Beijing, October 2012,
Contributed Papers and Invited Talks,
R. Feng, Ws. Lee, and Y. Sato (Eds.),
Springer, pp. 141145, 2014.

Y. Kawano and H. Sekigawa,
Quantum Fourier Transform over Symmetric GroupsImproved Result,
ACM Communications in Computer Algebra, Vol. 48, No. 3,
Issue 181, pp. 127129, 2014.

H. Sekigawa,
The Nearest Polynomial to Multiple Given Polynomials with a
Given Zero,
Proc. 2014 Symposium on SymbolicNumeric Computation (SNC2014),
pp. 144145, 2014.
2013

K. Shirayanagi and H. Sekigawa,
Intervalsymbol method with correct zero rewriting: Reducing exact
computations to obtain exact results,
Proc. 18th Asian Technology Conference in Mathematics (ATCM2013)
, pp. 226235, 2013.

H. Sekigawa and K. Shirayanagi,
Computing a Perturbation Bound for Preserving the Number of Common
Zeros of a Polynomial System,
Proc. 18th Asian Technology Conference in Mathematics
(ATCM2013),
pp. 145154, 2013.

Y. Kawano and H. Sekigawa,
Quantum Fourier Transform over Symmetric Groups,
Proc. International Symposium on Symbolic and Algebraic Computation
(ISSAC2013), pp. 227234, 2013.
2012

H. Sekigawa and K. Shirayanagi,
Maximal Perturbation for Preserving the Number of Solutions of a
Polynomial System,
ACM Communications in Computer Algebra, Vol. 46, No. 3,
Issue 181, pp. 120121, 2012.
2011

H. Sekigawa,
Computing the nearest polynomial with a zero in a given domain by
using piecewise rational functions,
Journal of Symbolic Computation, Vol. 46, Issue 12,
pp. 13181335, 2011.

Y. Kawano and H. Sekigawa,
Algorithm for QFT Circuits on Symmetric Groups,
Proc. Asian Conference on Quantum Information Science (AQIS2011),
pp. 207208, 2007.

H. Sekigawa and K. Shirayanagi,
Isolated Real Zero of a Real Polynomial System under Perturbation,
ACM Communications in Computer Algebra, Vol. 45, No. 2,
Issue 176, pp. 131132, 2011.
2010

H. Sekigawa and K. Shirayanagi,
Solvability of Bivariate Polynomial Systems under Perturbation,
ACM Communications in Computer Algebra, Vol. 44, No. 3,
Issue 173, pp. 147148, 2010.

Siegfried M. Rump and H. Sekigawa,
The ratio between the Toeplitz and the unstructured condition number,
Numerical Methods for Structured Matrices and ApplicationsThe Georg
Heinig Memorial Volume (Operator Theory: Advances and Applications,
Vol. 199),
Bini, D.A., Mehrmann, V., Olshevsky, V., Tyrtyshnikov, E., and van Barel,
M. (Eds.), Birkhaeuser, pp. 397419, 2010.
2009

H. Sekigawa,
A Sequence of Nearest Polynomials with Given Factors,
Proc. of The Joint Conference of Asian Symposium on Computer
Mathematics 2009 (ASCM2009) and International Conference on
Mathematical Aspects of Computer and Information Sciences 2009
(MACIS2009),
pp. 187190, 2009.

H. Nakayama and H. Sekigawa,
Determining divisibility between polynomials with inexact coefficients,
ACM Communications in Computer Algebra, Vol. 43, No. 3,
Issue 169, pp. 9094, 2009.

K. Shirayanagi and H. Sekigawa,
Reducing Exact Computations to Obtain Exact Results Based on
Stabilization Techniques,
Proc. International Workshop on SymbolicNumeric Computation 2009
(SNC2009), pp. 191197, 2009.

H. Sekigawa,
On Real Factors of Real Interval Polynomials,
Journal of Symbolic Computation, Vol. 44, Issue 7, pp. 908922, 2009.

Y. Nakajima, Y. Kawano, H. Sekigawa, M. Nakanishi, S. Yamashita,
and Y. Nakashima,
Synthesis of Quantum Circuits for dlevel Systems by using
CosineSine Decomposition,
Quantum Information and Computation,
Vol. 9, No. 5&6, pp. 423443, 2009.

H. Sekigawa,
Combining Symbolic and Numeric Computation,
(in Japanese),
IPSJ Magazine,
Vol. 50, No. 4, pp. 342348, 2009.
2008

K. Shirayanagi and H. Sekigawa,
A New Groebner Basis Conversion Method Based on the Stabilization
Techniques,
Theoretical Computer Science, Vol. 409, pp. 311317, 2008.

H. Sekigawa,
The Nearest Polynomial with a Zero in a Given Domain,
Theoretical Computer Science, Vol. 409, pp. 282291, 2008.

H. Sekigawa,
The Nearest Real Polynomial with a Real Multiple Zero in a Given
Real Interval,
Proc. Asian Symposium on Computer Mathematics 2007 (ASCM2007),
Lecture Notes in Computer Science 5081, pp. 3241, 2008.

H. Sekigawa,
The Nearest Polynomial with a Zero in a Given Domain from a
Geometrical Viewpoint,
Proc. International Symposium on Symbolic and Algebraic Computation
(ISSAC2008), pp. 287294, 2008.

Y. Nakajima, Y. Kawano, and H. Sekigawa,
Efficient Quantum Circuits for Approximating the Jones Polynomial,
Quantum Information and Computation,
Vol. 8, No. 5, pp. 489500, 2008.
2007

H. Sekigawa and K. Shirayanagi,
On the Location of Pseudozeros of a Complex Interval Polynomial,
Mathematics in Computer Science,
Vol. 1, No. 2, pp. 321335, 2007.

Y. Nakajima, Y. Kawano, and H. Sekigawa,
Synthesis of Quantum Circuits for dlevel Systems,
Proc. Asian Conference on Quantum Information Science (AQIS2007),
pp. 135136, 2007.

H. Sekigawa,
On Real Factors of Real Interval Polynomials,
Proc. International Symposium on Symbolic and Algebraic Computation
(ISSAC2007), pp. 331338, 2007.

P. Khungurn, H. Sekigawa, and K. Shirayanagi,
Minimum Converging Precision of the QRFactorization Algorithm for
Real Polynomial GCD,
Proc. International Symposium on Symbolic and Algebraic Computation
(ISSAC2007), pp. 227234, 2007.

H. Sekigawa,
The Nearest Polynomial with a Zero in a Given Domain,
Proc. International Workshop on SymbolicNumeric Computation 2007
(SNC2007), pp. 190196, 2007.

H. Sekigawa and K. Shirayanagi,
On the Location of Zeros of an Interval Polynomial,
SymbolicNumeric Computation,
D. Wang and L. Zhi (eds.), Birkhaeuser, pp. 167184, 2007.
2006

H. Sekigawa and K. Shirayanagi,
Locating Real Multiple Zeros of a Real Interval Polynomial
(in Japanese),
Journal of Japan Society for Symbolic and Algebraic Computation,
Vol. 13, No. 1, pp. 6871, 2006.

Y. Nakajima, Y. Kawano, and H. Sekigawa,
Quantum Circuit Design
(in Japanese),
IPSJ Magazine,
Vol. 47, No. 12, pp. 13351340, 2006.

T. Moriya, N. Harada, Y. Kamamoto, and H. Sekigawa,
MPEG4 ALSInternational Standard for Lossless Audio Coding,
NTT Technical Review, Vol. 4, No. 8, pp. 4045, 2006.

H. Sekigawa and K. Shirayanagi,
Locating Real Multiple Zeros of a Real Interval Polynomial,
Proc. International Symposium on Symbolic and Algebraic Computation
(ISSAC2006), pp. 310317, 2006.

K. Miyamoto, W. Yamamoto, H. Sekigawa, and K. Shirayanagi,
Deductive System for Humanlike Proofs in Geometry,
Proc. 13th Symposium on the Integration of Symbolic Computation and
Mechanized Reasoning 2006 (Calculemus'06),
pp. 520, 2006.
 H. Sekigawa and K. Shirayanagi,
On the Location of Zeros of an Interval Polynomial (in Japanese),
IEICE Trans. A,
Vol. J89A, No. 3, pp. 199216, 2006.

N. Harada, T. Moriya, H. Sekigawa, K. Shirayanagi, and Y. Kamamoto,
Lossless Compression of IEEE754 FloatingPoint Signal in ISO/IEC
MPEG4 Audio Lossless Coding (ALS) (in Japanese),
IEICE Trans. B,
Vol. J89B, No. 2, pp. 204213, 2006.

Y. Nakajima, Y. Kawano, and H. Sekigawa,
A New Algorithm for Producing Quantum Circuits using KAK
Decompositions,
Quantum Information & Computation,
Vol. 6, No. 1, pp. 6780, 2006.
2005

H. Sekigawa and K. Shirayanagi,
On the Location of Zeros of a Real Interval Polynomial
(in Japanese),
Journal of Japan Society for Symbolic and Algebraic Computation,
Vol. 12. No. 2, pp. 3538, 2005.

H. Sekigawa and K. Shirayanagi,
On the Location of Pseudozeros of a Complex Interval Polynomial,
Proc. Asian Symposium on Computer Mathematics (ASCM2005),
pp. 231234, 2005.

H. Nakajima, Y. Kawano, and H. Sekigawa,
An Algorithm for Decomposing Unitary Matrices using Cartan
Decomposition,
Abstracts of 11th International Conference on Applications of
Computer Algebra (ACA'2005), p. 24, 2005.

H. Sekigawa and K. Shirayanagi,
On the Location of Zeros of a Complex Interval Polynomial,
Abstracts of 11th International Conference on Applications of
Computer Algebra (ACA'2005), p. 15, 2005.

H. Sekigawa and K. Shirayanagi,
On the Location of Zeros of an Interval Polynomial,
Proc. International Workshop on SymbolicNumeric Computation 2005
(SNC2005), pp. 144165, 2005.

Y. Kawano, K. Kimura, H. Sekigawa, M. Noro, and K. Shirayanagi,
Exact CNOT on an ExchangeOnly Quantum Computer (in Japanese),
Journal of Japan Society for Symbolic and Algebraic Computation,
Vol. 11. No. 2, pp. 5558, 2005.

Y. Kawano, K. Kimura, H. Sekigawa, M. Noro, K. Shirayanagi,
M. Kitagawa, and M. Ozawa,
Existence of the Exact CNOT on a Quantum Computer with the
Exchange Interaction,
Quantum Information Processing, Vol. 4, No. 2, pp. 6585,
2005.

N. Harada, T. Moriya, H. Sekigawa, and K. Shiaryanagi,
Lossless Compression of IEEE Floatingpoint Audio using Approximate
Common Factor Coding and MaskedLZ Compression,
Poster presentation at
AES 118th Convention, 2005.
2004
 H. Sekigawa,
Zero Determination of Algebraic Numbers using Approximate
Computation (in Japanese), Bulletin of the Japan Society for
Industrial and Applied Mathematics, Vol. 14, No. 4, pp. 7578,
2004.
 K. Miyamoto, K. Ohya, H. Sekigawa, and K. Shirayanagi,
An Efficient Method of Finding Auxiliary Lines in Automated Geometry
Theorem Proving
(in Japanese), Proc. of the RIMS Workshop "Computer
AlgebraDesign of Algorithms, Implementations and Applications,"
Kokyuroku 1395, pp. 157163, Research Institute for Mathematical
Sciences, Kyoto Univ., 2004.
 Y. Kawano, K. Kimura, and H. Sekigawa,
On Quantum Gates in DecoherenceFree Subspaces
(in Japanese), Technical Report of IEICE,
COMP200423, pp. 3339, 2004.
2003
 K. Miyamoto, H. Sekigawa, K. Shirayanagi, and F. Machida,
On a Method for Automated Generation of Readable Proofs in
Euclidean Geometry
(in Japanese), Proc. of the RIMS Workshop "Computer
AlgebraAlgorithms, Implementations and Applications,"
Kokyuroku 1335, pp. 2027, Research Institute for Mathematical
Sciences, Kyoto Univ., 2003.
2002
 K. Shirayanagi and H. Sekigawa,
New Scientific ComputingSymbolicNumeric Algebra
(in Japanese),
NTT R&D, Vol. 51, No. 10, pp. 778783, 2002.
2000
 H. Sekigawa,
A Remark on the Polynomial Determining Superstable Points in the
Mandelbrot Set,
Josai Mathematical Monographs 2, NLA99 Computer Algebra,
pp. 1113, 2000.
 H. Sekigawa and K. Shirayanagi,
Automatic Algorithm Stabilization System,
Josai Mathematical Monographs 2, NLA99 Computer Algebra,
pp. 159168, 2000.
1999
 H. Sekigawa and K. Koyama,
Nonexistence Conditions of a Solution for the Congruence
x_{1}^{k}+...+x_{s}^{k}=N
(mod p^{n}),
Mathematics of Computation, Vol. 68, No. 227, pp. 12831297, 1999.
1998
 H. Sekigawa,
Using Interval Computation with the Mahler Measure for Zero
Determination of Algebraic Numbers,
Josai Information Sciences Researches,
Vol. 9, No. 1, pp. 8399, 1998.
1997
 K. Shirayanagi and H. Sekigawa,
An Interval Method Based on Zero Rewriting and its Application to
Sturm's Algorithm (in Japanese),
IEICE Trans. A,
Vol. J80A, No. 5, pp. 791802, 1997.
 K. Koyama, Y. Tsuruoka, and H. Sekigawa,
On Searching for Solutions of the Diophantine Equation
x^{3}+y^{3}+z^{3}=n,
Mathematics of Computation, Vol. 66, No. 218, pp. 841851, 1997.
1996
 H. Sekigawa,
Using Interval Arithmetic and Polynomial Norms to Determine Signs of
Algebraic Numbers,
Proc. 2nd Asian Symposium on Computer Mathematics (ASCM'96),
pp. 4353, 1996.
 H. Sekigawa,
An Interval Arithmetic with Algebraic Complexity to Determine the
Signs of Algebraic Expressions,
Abstracts of 4th International Symposium on Effective Methods in
Algebraic Geometry (MEGA'96),
p. 43, 1996.
1995
 H. Sekigawa and K. Shirayanagi,
Computing Diophantine Approximate Groebner Bases,
Proc. 1st Asian Technology Conference in Mathematics (ATCM'95),
pp. 717726, 1995.

H. Sekigawa and K. Shirayanagi,
Zero Rewriting in Interval Computation and Its Application to
Sturm's Algorithm,
Poster presentation at
International Symposium on Symbolic and Algebraic Computation
(ISSAC'95).

Tokyo University of Science

Faculty of Science Division I

Department of Applied Mathematics 