Masaaki Umehara

Profile Information

Affiliation: Professor, School of Computing, Tokyo Institute of Technology

Degree: Ph. D(University of Tsukuba)

Researcher number: 90193945
J-GLOBAL ID: 200901085966644943
researchmap Member ID: 1000030237

1984年慶應義塾大学工学部数理工学科卒，筑波大学大学院にて理学修士取得後，筑波大学助手，大阪大学助教授，広島大学教授，大阪大学教授を経て現在，東京工業大学教授，博士（理学）

Research Interests

Differential Geometry

Research Areas

Natural sciences / Geometry /

Research History

Apr, 2011 - Present

教授, 東京工業大学・情報理工学研究院
Apr, 2003 - Mar, 2011

教授, 大阪大学理学研究科
Apr, 1998 - Mar, 2003

教授, 広島大学理学研究科
Apr, 1996 - Mar, 1998

School of Science, Osaka University
Apr, 1994 - Mar, 1996

School of Science, Osaka University
Oct, 1991 - Mar, 1994

講師, 大阪大学教養部
Apr, 1987 - Sep, 1991

Institute of Mathematics, University of Tsukuba

Education

Apr, 1984 - Mar, 1987

筑波大学数学研究科博士課程で修士号取得後に退学
- 1984

Faculty of Engineering, Keio University
- 1984

Keio University

Awards

1995

幾何学賞(日本数学会)
日本数学会秋季賞, 特異点をもつ曲面およびローレンツ-ミンコフスキー空間内の曲面の微分幾何学, 日本数学会

梅原雅顕・山田光太郎

Papers

Umbilics of Surfaces in the Lorentz–Minkowski 3-Space

Naoya Ando, Masaaki Umehara

Results in Mathematics, 78(6), Sep 28, 2023
On the existence of four or more curved foldings with common creases and crease patterns

A. Honda, K. Naokawa, K. Saji, M. Umehara, K. Yamada

Beiträge zur Algebra und Geometrie / Contributions to Algebra and Geometry, 63(4) 723-761, Dec, 2022
Analytic extensions of constant mean curvature one geometric catenoids in de Sitter 3-space

S. Fujimori, Y. Kawakami, M. Kokubu, W. Rossman, M. Umehara, K. Yamada, S.-D. Yang

Differential Geometry and its Applications, 84 101924-101924, Oct, 2022
Isometric deformations of wave fronts at non-degenerate singular points

Atsufumi Honda, Kosuke Naokawa, Masaaki Umehara, Kotaro Yamada

Hiroshima Mathematical Journal, 50(3), Nov 1, 2020
Curved foldings with common creases and crease patterns

Atsufumi Honda, Kosuke Naokawa, Kentaro Saji, Masaaki Umehara, Kotaro Yamada

Advances in Applied Mathematics, 121 102083-102083, Oct, 2020
Cuspidal edges with the same first fundamental forms along a knot

Atsufumi Honda, Kosuke Naokawa, Kentaro Saji, Masaaki Umehara, Kotaro Yamada

Journal of Knot Theory and Its Ramifications, 29(07) 2050047-2050047, Jun, 2020
Improvement of the Bernstein-type theorem for space-like zero mean curvature graphs in Lorentz-Minkowski space using fluid mechanical duality

Shintaro Akamine, Masaaki Umehara, Kotaro Yamada

Proc. Amer. Math. Soc. Ser. B, 7(2) 17-27, Feb, 2020 Peer-reviewed
Duality on generalized cuspidal edges preserving singular set images and first fundamental forms

Atsufumi Honda, Kosuke Naokawa, Kentaro Saji, Masaaki Umehara, Kotaro Yamada

Journal of Singularities, 22, 2020
Space-like maximal surfaces containing entire null lines in Lorentz-Minkowski 3-space

Shintaro Akamine, Masaaki Umehara, Kotaro Yamada

Proc. Japan Acad. Ser. A Math. Sci. 95 (2019), 97–102, Nov, 2019 Peer-reviewed
Isometric realization of cross caps as formal power series and its applications

A. Honda, K. Naokawa, M. Umehara, K. Yamada

Hokkaido Mathematical Journal, 48(1) 1-44, Feb, 2019 Peer-reviewed
Hypersurfaces with light-like points in a Lorentzian manifold

M. Umehara, K. Yamada

Journal of Geometric Analysis, 29 3405-3437, 2019 Peer-reviewed
Analytic extension of exceptional constant mean curvature one catenoids in de Sitter 3-space

ROSSMAN FREMONT Wayne, FUJIMORI Shoichi, UMEHARA Masaaki, YAMADA Kotaro, KOKUBU Masatoshi, KAWAKAMI Yu

to appear in Math. J. Okayama Univ., -, 2019 Peer-reviewed
特異点の微分幾何学ー３次元時空の極大曲面をテーマにしてー

梅原雅顕

「応用数理」, 28(2) 86-89, Jun, 2018 Peer-reviewedInvited
Addendum: singularities of flat fronts in hyperbolic space

M. Kokubu, ROSSMAN FREMONT Wayne, Kentaro SAJI, M. Umehara, K. Yamada

Pacific J. Math, 294(2) 505-509, Feb, 2018 Peer-reviewed
Mixed type surfaces with bounded mean curvature in 3-dimensional space-times

Atsufumi Honda, Miyuki Koiso, Masatoshi Kokubu, Masaaki Umehara, Kotaro Yamada

DIFFERENTIAL GEOMETRY AND ITS APPLICATIONS, 52 64-77, Jun, 2017 Peer-reviewed
C-1-UMBILICS WITH ARBITRARILY HIGH INDICES

Naoya Ando, Toshifumi Fujiyama, Masaaki Umehara

PACIFIC JOURNAL OF MATHEMATICS, 288(1) 1-26, May, 2017 Peer-reviewed
ANALYTIC EXTENSION OF JORGE-MEEKS TYPE MAXIMAL SURFACES IN LORENTZ-MINKOWSKI 3-SPACE

Shoichi Fujimori, Yu Kawakami, Masatoshi Kokubu, Wayne Rossman, Masaaki Umehara, Kotaro Yamada

OSAKA JOURNAL OF MATHEMATICS, 54(2) 249-272, Apr, 2017 Peer-reviewed
Surfaces with light-like points in Lorentz-Minkowski 3-space with applications

Masaaki Umehara, Kotaro Yamada

Springer Proceedings in Mathematics and Statistics, 211 253-273, 2017 Peer-reviewed
Quadrics and Scherk towers

S. Fujimori, U. Hertrich-Jeromin, M. Kokubu, M. Umehara, K. Yamada

Monatsh Math., 186 249-279, 2017 Peer-reviewed
An index formula for a bundle homomorphism of the tangent bundle into a vector bundle of the same rank, and its applications

Kentaro Saji, Masaaki Umehara, Kotaro Yamada

JOURNAL OF THE MATHEMATICAL SOCIETY OF JAPAN, 69(1) 417-457, Jan, 2017 Peer-reviewed

Misc.

Null hypersurfaces in Lorentzian manifolds with the null energy condition

Shintaro Akamine, Atsufumi Honda, Masaaki Umehara, Kotaro Yamada

Oct 15, 2019
Bernstein-type theorem for zero mean curvature hypersurfaces without time-like points in Lorentz-Minkowski space

Shintaro Akamine, Atsufumi Honda, Masaaki Umehara, Kotaro Yamada

Bulletin of the Brazilian Mathematical Society, New Series (2020), 52(1) 175-181, Jul 3, 2019
Isometric deformations of wave fronts at non-degenerate singular points

Atsufumi Honda, Kosuke Naokawa, Masaaki Umehara, Kotaro Yamada

to appear in Hiroshima Mathematical Journal, Oct, 2017
ZERO MEAN CURVATURE SURFACES IN LORENTZ-MINKOWKI 3-SPACE WHICH CHANGE TYPE ACROSS A LIGHT-LIKE LINE (vol 52, pg 285, 2015)

S. Fujimori, Y. W. Kim, S. -E. Koh, W. Rossman, H. Shin, M. Umehara, K. Yamada, S. -D. Yang

OSAKA JOURNAL OF MATHEMATICS, 53(1) 289-292, Jan, 2016
Complete bounded null curves immersed in C-3 and SL(2, C) (vol 36, pg 119, 2009)

Francisco Martin, Masaaki Umehara, Kotaro Yamada

CALCULUS OF VARIATIONS AND PARTIAL DIFFERENTIAL EQUATIONS, 46(1-2) 439-440, Jan, 2013
Applications of a completeness lemma in minimal surface theory to various classes of surfaces (vol 43, pg 191, 2011)

Masaaki Umehara, Kotaro Yamada

BULLETIN OF THE LONDON MATHEMATICAL SOCIETY, 44 617-618, Jun, 2012
The duality between singular points and inflection points on wave fronts

Saji Kentaro, Umehara Masaaki, Yamada Kotaro

Osaka Journal of Mathematics, 47(2) 591-607, Jun, 2010
Asymptotic behavior of flat surfaces in hyperbolic 3-space

Masatoshi Kokubu, Wayne Rossman, Masaaki Umehara, Kotaro Yamada

JOURNAL OF THE MATHEMATICAL SOCIETY OF JAPAN, 61(3) 799-852, Jul, 2009
The geometry of fronts

Kentaro Saji, Masaaki Umehara, Kotaro Yamada

ANNALS OF MATHEMATICS, 169(2) 491-529, Mar, 2009
3次元双曲型空間の平均曲率1の曲面

名古屋大学多元数理考究録, 9, 2009
特異点をもつ曲線と曲面の幾何学

慶應義塾大学数理科学科レクチャーノート vol 38, 2009
Behavior of corank-one singular points on wave fronts

Kentaro Saji, Masaaki Umehara, Kotaro Yamada

KYUSHU JOURNAL OF MATHEMATICS, 62(1) 259-280, Mar, 2008
Flat fronts in hyperbolic 3-space and their caustics

Masatoshi Kokubu, Wayne Rossman, Masaaki Umehara, Kotaro Yamada

JOURNAL OF THE MATHEMATICAL SOCIETY OF JAPAN, 59(1) 265-299, Jan, 2007
Maximal surfaces with singularities in Mikowski space

Masaaki Umehara, Kotaro Yamada

Hokkaido Math. J., 35 13-40, 2006
Singularities of flat fronts in hyperbolic space

M Kokubu, W Rossman, K Saji, M Umehara, K Yamada

PACIFIC JOURNAL OF MATHEMATICS, 221(2) 303-351, Oct, 2005
Constructing mean curvature 1 surfaces in H^3 with irregular ends

Wayne Rossman, Masaaki Umehara, Kotaro Yamada

Clay Mathematics Proceedings (Global Theory of Minimal Surfaces), 2 561-584, 2005
Flat fronts in hyperbolic 3-space

M Kokubu, M Umehara, K Yamada

PACIFIC JOURNAL OF MATHEMATICS, 216(1) 149-175, Sep, 2004
A global theory of flexes of periodic functions

G Thorbergsson, M Umehara

NAGOYA MATHEMATICAL JOURNAL, 173 85-138, Mar, 2004
An analogue of the UP-iteration for constant mean curvature one surfaces in hyperbolic 3-space

C McCune, M Umehara

DIFFERENTIAL GEOMETRY AND ITS APPLICATIONS, 20(2) 197-207, Mar, 2004
Mean curvature 1 surfaces in hyperbolic 3-space with low total curvature I

Wayne Rossman, Masaaki Umehara, Kotaro Yamada

Hiroshima Math. J., 34(1) 21-56, 2004

Books and Other Publications

特異点をもつ曲線と曲面の微分幾何学

梅原雅顕, 佐治健太郎, 山田光太郎 (Role: Joint author)

丸善, Nov, 2017
曲線と曲面 : 微分幾何的アプローチ

梅原雅顕, 山田光太郎 (Role: Joint author)

裳華房, 2002 (ISBN: 9784785315313)
Differential and Symplectic Topology of Knots and Curves (American Mathematical Society Translations: Series 2, vol.190)

S. Tabachnikov (Role: Contributor, Gudlaugur Thorbergsson and Masaaki Umehara "A unified approach to the four vertex theorems II")

American Mathematical Society, 1999 (ISBN: 9780821813546)
Differential and Symplectic Topology of Knots and Curves (American Mathematical Society Translations: Series 2, vol.190)

S. Tabachnikov (Role: Contributor, A unified approach to the four vertex theorem I)

American Mathematical Society, 1999 (ISBN: 9780821813546)

Presentations

Hypersurfaces with light-like points in Lorentzian manifolds

UMEHARA Masaaki

15th International Workshop on Real and Complex Singularities, Brail, Jul 27, 2018 Invited
Surfaces with light-like points in Lorentz-Minkowski 3-space

梅原雅顕

International workshop "Geometry of Submanifolds and Integrable System"，大阪市立大学理学部, Mar 29, 2018 Invited
特異点の微分幾何学― ３次元時空の極大曲面をテーマにして―

梅原雅顕

日本応用数理学会2017年度年会・総合講演, Sep 7, 2017 Invited
特異点をもつ曲面の幾何学

梅原雅顕

第６３回幾何学シンポジウム@岡山大学, Aug 30, 2016 Invited
Indices of isolated umbilics on surfaces

UMEHARA Masaaki

Geometric Analysis in Geometery and Topology, Nov 12, 2015 Invited
Intrinsic properties of surfaces with singularities

UMEHARA Masaaki

Real Singularities and applications, Feb 17, 2014 Invited

Professional Memberships

Math. Soc. Japan

Research Projects

ワイエルストラス表現公式の類似と特異点における延長問題

科学研究費助成事業, 基盤研究(B), 日本学術振興会, Apr, 2022 - Mar, 2027

山田光太郎, 梅原雅顕
Differential geometrey of singularities and its applications

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, Apr, 2021 - Mar, 2026
Singularities of surfaces and hypersurfaces in Lorentzian space forms

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, Apr, 2017 - Mar, 2022
Studies on diameter conjecture on flat tori in the unit sphere

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, Apr, 2015 - Mar, 2018

Kitagawa Yoshihisa, AIHARA Yosihiro, UMEHARA Masaaki
Surfaces with singularities in space-times and Weierstrass-type representation formulas

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, Apr, 2014 - Mar, 2018

Yamada Kotaro, Masaaki Umehara
特異点をもつ曲線，曲面と超曲面の微分幾何学的研究の推進

基盤研究A 26247005, JSPS, Apr, 2013 - Mar, 2018

梅原雅顕
Studies on some open problems concerning flat tori in odd dimensional spheres

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, Apr, 2012 - Mar, 2015

KITAGAWA Yoshihisa, AIHARA Yoshihiro, UMEHARA Masaaki
Development of Integrable Geometry

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, Apr, 2011 - Mar, 2015

Miyaoka Reiko, KOTANI Motoko, NISHINOU Takeo, UEHARA Taketo, MATSUURA Nozomu, IWASAKI Katsunori, IRITANI Hiroshi, KAJIWARA Kenji, NAGATOMO Yasuyuki, NOMURA Takaaki, YAMADA Kotaro, ISHIKAWA Goo, UMEHARA Masaaki, GUEST Martin, SHODA Toshihiro, FUTAKI Akito, FUJIOKA Atsushi, RASSMAN Wayne, TAMARU Hiroshi
Differential geometric research on surfaces admitting singularities and its application

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, Apr, 2010 - Mar, 2015

KOKUBU Masatoshi, UMEHARA Masaaki, YAMADA Kotaro, ROSSMAN Wayne, FUJIMORI Shoichi, YAMAMOTO Ou, IRIE Hiroshi
A research on the geometric singularities of non-linear phenomena

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, Apr, 2010 - Mar, 2014

IZUMIYA Shyuichi, ISHIKAWA Goo, TERAO Hiroaki, TONEGAWA Yoshihiro, OHMOTO Toru, ONO Kaoru, UMEHARA Masaaki, KOIKE Shigeaki
Weierstrass-type representation formulas and their application to surfaces with singularities

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, Apr, 2009 - Mar, 2014

YAMADA Kotaro, UMEHARA Masaaki, WAYNE Rossman, YOSHIDA Masaaki, KUROSE Takashi, KOKUBU Masatoshi, FUJIMORI Shoichi, KAWAKAMI Yu, HONDA Atsufumi
Geometry of Ricci solitons on complex manifolds

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Japan Society for the Promotion of Science, Apr, 2008 - Mar, 2013

MABUCHI Toshiki, GOTO Ryushi, UMEHARA Masaaki, SASAKI Takeshi, NAKAGAWA Yasuhiro, HASEGAWA Keizo, NAKAJIMA Hiraku
特異点をもつ曲線，曲面と超曲面の幾何学

基盤研究A 22244006, JSPS, Apr, 2010 - Mar, 2013

梅原雅顕
Geometric structures defined by differential forms (Calabi-Yau structures, generalized Kaeher structures)

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, 2010 - 2012

GOTO Ryushi, OGUISO Keiji, FUJIKI Akira
Fusion of geometry and the theory of integrable systems

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Japan Society for the Promotion of Science, 2007 - 2010

MIYAOKA Reiko, OHNITA Yoshihiro, MOTOKO Kotani, SASAKI Takeshi, IWASAKI Katsunori, OYSU Yukio, KAJIWARA Kenji, NAGATOMO Yasuyuki, NAKAYAAHIKI Atsushi, YAMADA Kotaro, FUTAKI Akito, MARTIN Guest, WAYNE Rossman, SHODA Toshihiro, IRITANI Hiroshi, ISHIKAWA Goo, UMEHARA Masaaki, KAWAKUBO Satoshi, TAMARU Hiroshi, FUJIOKA Atsushi, MATSUURA Nozomu, NISHINOU Takeo
Heegaard structures and geometric structures of 3-manifolds

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, 2006 - 2009

SAKUMA Makoto, KAMADA Seiichi, NAGAI Toshitaka, MATSUMOTO Takao, UMEHARA Masaaki, OHSHIKA Ken'ichi, KONNO Kazuhiro, MABUCHI Toshiki, WADA Masaaki, MIYACHI Hideki, KOBAYASHI Tsuyoshi, YAMASHITA Yasushi, MORIMOTO Kanji, NAKANISHI Toshihiro, KOMORI Yohei, AKIYOSHI Hirotaka
Differential Geometry and Partial Differential Equations as an application of Singularity theory

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, 2006 - 2009

IZUMIYA Shyuichi, ISHIKAWA Goo, ONO Kaoru, YAMAGUCHI Keizo, OHMOTO Toru, TONEGAWA Yoshihiro, UMEHARA Masaaki, KOIKE Shigeaki, UMEHAPR Masaaki, KOIKE Shigeaki
Generalizations of Weierstrass-type representation formula and their applications to theory of surface with singularities

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, 2006 - 2008

YAMADA Kotaro, MIYAOKA Reiko, SAEKI Osamu, OTSU Yukio, NAGATOMO Yasuyuki, TAKAYAMA Haruko, UMEHARA Masaaki, KUROSE Takashi, KOKUBU Masatoshi, FUJIMORI Shoichi, SHODA Toshihiro, TAKAHASHI Masaro
Existence Problem of Fxtremal Metran and Degeneration of Balanced Metrics

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (A), Japan Society for the Promotion of Science, 2004 - 2007

MABUCHI Toshiki, NAKAJIMA Hiraku, ONO Kaoru, ITOH Mitsuhiro, UMEHARA Masaaki, GOTO Ryushi
The global behavior of curves and surfaces in space forms

Grants-in-Aid for Scientific Research, Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, 2003 - 2006

UMEHARA Masaaki, KOISO Norihito, YAMADA Kotaro, ROSSMAN Wayne F, KOKUBU Masatoshi, INOGUCHI Junichi

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