論文

• Kentaro Saji, Masaaki Umehara, Kotaro Yamada. Deformations of cuspidal edges in a 3-dimensional space form, Kodai Math. J., Vol. 44, Mar. 2024.
• Masaaki Umehara, Naoya Ando. Umbilics of surfaces in the Lorentz-Minkowski 3-space, Results Math., Vol. 78, Sept. 2023.
• Atsufumi Honda, Naokawa Kosuke, Kentaro Saji, Masaaki Umehara, Kotaro Yamada. Symmetries of cross caps, TOHOKU MATH. J., Vol. 75, Mar. 2023.
• Shoichi Fujimori, Yu Kawakami, Masatoshi Kokubu, Masaaki Umehara, Wayne Rossman, Kotaro Yamada, Seong-Deog Yang. Analytic extensions of constant mean curvature one geometric catenoids in de Sitter 3-space, Differential geometry and its applications, Volume 84, Oct. 2022.
• Atsufumi Honda, Naokawa Kosuke, Kentaro Saji, Masaaki Umehara, Kotaro Yamada. A generalization of zakalyukin's lemma, and symmetries of surface singularities, Journal of Singularities, Vol. 25, Oct. 2022.
• Atsufumi Honda, Kosuke Naokawa, Kentaro Saji, Masaaki Umehara, Kotaro Yamada. On the existence of four or more curved foldings with common creases and crease patterns, Beiträge zur Algebra und Geometrie / Contributions to Algebra and Geometry, Oct. 2021.  公式リンク  
  
• Masaaki Umehara, Kotaro Yamada. Hypersurfaces with light-like points in a Lorentzian manifold II, Kodai Math. J., Vol. 44, No. 1, Mar. 2021.
• Atsufumi Honda, Naokawa Kosuke, Kotaro Yamada, Masaaki Umehara. Isometric deformations of wave fronts at non-degenerate singular points, HIROSHIMA MATH. J., Vol. 50, No. 3, Page 269--312, Nov. 2020.
• Atsufumi Honda, Naokawa Kosuke, Masaaki Umehara, Kotaro Yamada. Curved foldings with common creases and crease patterns, Adv. Appl. Math., Vol. 121, Page 25, Oct. 2020.
• Atsufumi Honda, Naokawa Kosuke, Masaaki Umehara, Kotaro Yamada. Duality on generalized cuspidal edges preserving singular set images and first fundamental forms, J. of Singul., Vol. 22, pp. 59--91, Aug. 2020.
• Atsufumi Honda, Naokawa Kosuke, Masaaki Umehara, Kotaro Yamada. Cuspidal edges with the same first fundamental forms along a knot, ：J. Knot Theory Ramifications, Vol. 29, No. 7, June 2020.
• Akamine Shintaro, Masaaki Umehara, Kotaro Yamada. Improvement of the Bernstein-type theorem for space-like zero mean curvature graphs in Lorentz-Minkowski space using fluid mechanical duality, Proc. Amer. Math. Soc. Ser. B, Vol. 7, pp. 17-27, Feb. 2020.
• S. Akamine, A. Honda, M. Umehara, K.Yamada. Bernstein-type theorem for zero mean curvature hypersurfaces without time-like points in Lorentz-Minkowski space, Bulletin of the Brazilian Mathematical Society, New Series, https://doi.org/10.1007/s00574-020-00196-8, Jan. 2020.
• K. Enomoto, Y. KItagawa, M. Umehara. Extrinsic diameter of immersed flat tori in the 3-sphere II, Journal of Geometry, Vol. 111, 0047-2468/20/010001-26, Jan. 2020.
• M. Umehara, K. Yamada. Hypersurfaces with light-like points in a Lorentzian manifold, Journal of Geometric Analysis, Vol. 29, pp. 3405-3437, Dec. 2019.
• S. Akamine, M. Umehara, K.Yamada. Space-like maximal surfaces containing entire null lines in Lorentz-Minkowski 3-space, Proc. Japan Acad. Ser.A, Math. Sci., Vol. 95, No. 9, pp. 97-102, Oct. 2019.
• Atsufumi Honda, Naokawa Kosuke, Masaaki Umehara, Kotaro Yamada. Isometric realization of cross caps as formal power series and its applications, Hokkaido Mathematical Journal, Vol. 48, No. 1, pp. 1-44, Feb. 2019.
• Shoichi Fujimori, Yu Kawakami, Masatoshi Kokubu, Wayne Rossman, Masaaki Umehara, Kotaro Yamada. Exceptional constant mean curvature one catenoids in de Sitter 3-space, Jan. 2019.
• Shoichi Fujimori, Udo Hertrich-Jeromin, Masatoshi Kokubu, Masaaki Umehara, Kotaro Yamada. Quadrics and Scherk towers, Monatshefte für Mathematik, Springer-Verlag, July 2017.
• Atsufumi Honda, Miyuki Koiso, Masatoshi Kokubu, Masaaki Umehara, Kotaro Yamada. Mixed type surfaces with bounded mean curvature in 3-dimensional space-times, Differential Geometry and its Applications, Vol. 52, pp. 64-77, June 2017.
• Naoya Ando, Toshfumi Fujiyama, Masaaki Umehara. C^1-umbilics with arbitrary high indices, Vol. 288, No. 1, May 2017.
• FUJIMORI SHOICHI, KAWAKAMI YU, KOKUBU MASATOSHI, ROSSMAN WAYNE, UMEHARA MASAAKI, YAMADA KOTARO. ANALYTIC EXTENSION OF JORGE-MEEKS TYPE MAXIMAL SURFACES IN LORENTZ-MINKOWSKI 3-SPACE, Osaka Journal of Mathematics, Osaka University and Osaka City University, Departments of Mathematics, Vol. 54, No. 2, pp. 249-272, Mar. 2017.
• Shoichi Fujimori, Yu Kawakami, Masatoshi Kokubu, Wayne Rossman, Masaaki Umehara, Kotaro Yamada. Zero mean curvatrue entire graphs of mixed type in Lorentz-Minkowski 3-space, The Quarterly Journal of Mathematics, Volume 67, No. 4, pp. 801-837, Dec. 2016.
• Kosuke Naokawa, Masaaki Umehara, Kotaro Yamada. Isometric deformations of cuspidal edges, Tohoku Math. J., Vol. 68, No. 1, pp. 73-90, Mar. 2016.
• Udo Hertrich-Jeromin, Yshihiko Suyama, Masaaki Umehara, Kotaro Yamada. A duality for conformally flat hypersurfaces, Beitraege zur Algebra und Geometrie / Contributions to Algebra and Geometry, Vol. 56, No. 2, 655-676, Oct. 2015.
• Shoichi Fujimori, Young Wook Kim, Sung-Eun Koh, Wayne Rossman, Heayong Shin, Masaaki Umehara, Kotaro Yamada, Seong-Deog Yang. Zero mean curvature surfaces in Lorentz-Minkowski 3-space and 2-dimensional fuluid mechanics, Math. J. Okayama Univ., Vol. 57, No. 1, pp. 173-200, Jan. 2015.
• Shoichi Fujimori, Young Wook Kim, Sung-Eun Koh, Wayne Rossman, Heayong Shin, Masaaki Umehara, Kotaro Yamada, Seong-Deog Yang. Zero mean curvature surfaces in Lorentz-Minkowski 3-space which change type across a light-like line, OSAKA JOURNAL OF MATHEMATICS, Vol. 57, No. 1, pp. 285-297, Jan. 2015.
• hiro gounai, Masaaki Umehara. Caustics of convex curves, Journal of Knot Theory and Its Ramifications, Vol. 23, No. 10, pp. 1-28, Sept. 2014.
• Hasegawa Masaru, Honda Atsufumi, Kosuke Naokawa, Masaaki Umehara, Kotaro Yamada. Intrinsic invariants of Cross Caps, Selecta Math. New Ser., Vol. 20, pp. 769--785, July 2014.
• Francisco Martin, Masaaki Umehara, Kotaro Yamada. Flat surfaces in hyperbolic 3-space whose hyperbolic Gauss maps are bounded, Revista Matemática Iberoamericana, Vol. 30, No. 1, pp. 309--316, Mar. 2014.
• Shoichi Fujimori, Wayne Rossman, Masaaki Umehara, Kotaro Yamada, Seong-Deog Yang. Embedded triply periodic zero mean curvature surfaces, Michigan Math. J., Vol. 63, No. 1, pp. 189--207, Mar. 2014.
• Leoner Ferrer, Francisco Martin, Masaaki Umehara, Kotaro Yamada. A construction of a complete bounded null curves in C^3, Kodai Mathematical Journal, Vol. 37, No. 1, pp. 59--96, Mar. 2014.
• Gudlaugur Thorbergsson, Masaaki Umehara. A refinement of Foreman's four vertex theorem and its dual version, Kyoto Journal of Mathematics, Vol. 52, Page 743--758, June 2013.
• Syuntaro Oono, Tetsuya Ozawa, Masaaki Umehara. Closed Planar curves without inflections, Proc. Amer. Math. Soc., Vol. 141, Page 651--665, Feb. 2013.
• Shoichi Fujimori, S.E. Koh, Y.W. Kim, Wayne Rossman, H. Shin, Hedenobu Takahashi, Masaaki Umehara, Kotaro Yamada, Seong-Deog Yang. Zero mean curvature surface in L^3 containing a light-like line, C. R. Acad. Sxi. Paris, Ser. I, Vol. 350, Page 975--978, Nov. 2012.
• Shohei Shiba, Masaaki Umehara. The behavior of curvature functions at cusps and inflection points, Differential Geometry and its applications, Vol. 30, pp. 285--299, May 2012.
• Kentaro Saji, Masaaki Umehara, Kotaro Yamada. Coherent tangent bundles and Gauss-Bonnet formulas for wave fronts, Journal of Geometric Analysis, Vol. 22, pp. 883--409, Apr. 2012.
• Kokubu Masatoshi, Masaaki Umehara. Orientability of linear Weingarten surfaces, spacelike CMC-1 surfaces and maximal surfaces, Mathematische Nachrichten, Vol. 384, pp. 1903--1918, June 2011.
• Shoichi Fujimori, Yu Kawakami, Masatoshi Kokubu, Wayne Rossman, M. Umehara, Kotaro Yamada. CMC-1 trinoids in H3 and metrics of constant curvature one with conical singularities on S^2, Prooc. Japan Academy Ser. A, Vol. 87, pp. 144--149, June 2011.
• Kentaro Saji, Masaaki Umehara, Kotaro Yamada. A_2-singularities of hypersurfaces with non-negative sectional curvature in Euclidean space, Kodai Math. J., Vol. 34, pp. 390--409, June 2011.
• Yoshhisa Kitagawa, Masaaki Umehara. Extrinsic diameter of immersed flat tori in S^3, Geometriae Dedicata, Vol. 155, pp. 105--140, June 2011.
• Masaaki Umehara, Kotaro Yamada. Applications of a completeness lemma in minimal surface theory to various classes of surfaces, Bull. Lond. Math. Soc., Volume 43, No. 1, Page 191-199, May 2011.
• Masaaki Umehara. A simplification of the proof of Bol's conjecture on sextactic points, Proc. Japan Acad. Ser. A Math. Sci., Volume 87, No. 1, Page 10-12, Jan. 2011.
• Kentaro Saji, Masaaki Umehara, Kotaro Yamada. Singularities of Blaschke normal maps of convex surfaces, C. R. Math. Acad. Sci. Paris, Vol. 348, No. 11-12, Page 665-668, June 2010.
• Kentaro Saji, Masaaki Umehara, Kotaro Yamada. The duality between singular points and inflection points on wave fronts, Osaka J. Math., Vol. 47, No. 2, Page 591-607, Apr. 2010.
• Shoichi Fujimoro, Wayne Rossman, Masaaki Umehara, Kotaro Yamada, Seong-Deog Yang. New maximal surfaces in Minkowski 3-space with arbitrary genus and their cousins in de Sitter 3-space, Results Math., Vol. 56, No. 4, Page 41-82, Dec. 2009.
• Kentaro Saji, Masaaki Umehara, Kotaro Yamada. Ak singularities of wave fronts, Math. Proc. Cambridge Philos. Soc., Vol. 146, No. 3, Page 731-746, Sept. 2009.
• Masatoshi Kokubu, Wayne Rossman, Masaaki Umehara, Kotaro Yamada. Asymptotic behavior of flat surfaces in hyperbolic 3-space, J. Math. Soc. Japan, Vol. 61, No. 3, Page 799-852, Sept. 2009.
• Shoichi Fujimori, Wayne Rossman, Masaaki Umehara, Kotaro Yamada, Seong-Deog Yang. Spacelike mean curvature one surfaces in de Sitter 3-space, Comm. Anal. Geom., Vol. 17, No. 3, Page 383-427, Sept. 2009.
• Francisco Martin, Masaaki Umehara, Kotaro Yamada. Complete bounded holomorphic curves immersed in C^2 with arbitrary genus, Proc. Amer. Math. Soc., Vol. 137, No. 10, Page 3437-3450, June 2009.
• Kentaro Saji, Masaaki Umehara, Kotaro Yamada. The geometry of fronts, Ann. of Math., Vol. 169, No. 2, Page 491-529, Apr. 2009.
• Satoko Murata, Masaaki Umehara. Flat surfaces with singularities in Euclidean 3-space, J. Differential Geom., Vol. 82, No. 2, Page 279-316, Apr. 2009.
• Francisco Martin, Masaaki Umehara, Kotaro Yamada. Complete bounded null curves immersed in C^3 and SL(2,C), Calc. Var. Partial Differential Equations, Vol. 36, No. 1, Feb. 2009.
• SAJI Kentaro, UMEHARA Masaaki, YAMADA Kotaro. An index formula for a bundle homomorphism of the tangent bundle into a vector bundle of the same rank, and its applications, Journal of the Mathematical Society of Japan, 一般社団法人 日本数学会, Vol. 69, No. 1, pp. 417-457.

著書

• 梅原 雅顕, 一木 俊助. これからの集合と位相, 裳華房, Nov. 2022.
• 梅原雅顕, 山田光太郎, 佐治健太郎. 特異点をもつ曲線と曲面の幾何学, 特異点をもつ曲線と曲面の微分幾何学, 丸善出版, Dec. 2017.
• Masaaki Umehara, Kotaro Yamada. Differential Geometry of Curves and Surfaces, Differential Geometry of Curves and Surfaces, World Scientific, May 2017.
• 梅原雅顕, 山田光太郎. 曲線と曲面・微分幾何的アプローチ（改訂版）, 裳華房, Feb. 2015.
• 梅原雅顕, 山田光太郎. 曲線と曲面, 曲線と曲面-微分幾何的アプローチ-, 裳華房, June 2002.

国際会議発表 (査読有り)

• Masaaki Umehara, Kotaro Yamada. Surfaces with light-like points in Lorentz-Minkowski 3-space with applications, International Meeting on Lorentzian Geometry GELOMA 2016, Springer Proceedings in Mathematics & Statisticsbook series (PROMS, volume 211), Springer International Publishing, Vol. 211, pp. 253--273, Mar. 2018.

国内会議発表 (査読なし・不明)

• 梅原雅顕. 曲面の臍点の指数について, 福岡大学微分幾何研究会, Nov. 2015.

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