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Shigeo Sasaki
Shigeo Sasaki () (18 November 1912 Yamagata Prefecture, Japan – 14 August 1987 Tokyo) was a Japanese mathematician working on differential geometry who introduced Sasaki manifolds. He retired from Tohoku University , or is a Japanese national university located in Sendai, Miyagi in the Tōhoku Region, Japan. It is informally referred to as . Established in 1907, it was the third Imperial University in Japan and among the first three Designated National ...'s Mathematical Institute in April 1976. Publications * References * * 20th-century Japanese mathematicians 1912 births 1987 deaths {{Japan-mathematician-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Differential Geometry
Differential geometry is a mathematical discipline that studies the geometry of smooth shapes and smooth spaces, otherwise known as smooth manifolds. It uses the techniques of differential calculus, integral calculus, linear algebra and multilinear algebra. The field has its origins in the study of spherical geometry as far back as antiquity. It also relates to astronomy, the geodesy of the Earth, and later the study of hyperbolic geometry by Lobachevsky. The simplest examples of smooth spaces are the plane and space curves and surfaces in the three-dimensional Euclidean space, and the study of these shapes formed the basis for development of modern differential geometry during the 18th and 19th centuries. Since the late 19th century, differential geometry has grown into a field concerned more generally with geometric structures on differentiable manifolds. A geometric structure is one which defines some notion of size, distance, shape, volume, or other rigidifying structu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sasaki Manifold
In differential geometry, a Sasakian manifold (named after Shigeo Sasaki) is a contact manifold (M,\theta) equipped with a special kind of Riemannian metric g, called a ''Sasakian'' metric. Definition A Sasakian metric is defined using the construction of the ''Riemannian cone''. Given a Riemannian manifold (M,g), its Riemannian cone is the product :(M\times ^)\, of M with a half-line ^, equipped with the ''cone metric'' : t^2 g + dt^2,\, where t is the parameter in ^. A manifold M equipped with a 1-form \theta is contact if and only if the 2-form :t^2\,d\theta + 2t\, dt \cdot \theta\, on its cone is symplectic (this is one of the possible definitions of a contact structure). A contact Riemannian manifold is Sasakian, if its Riemannian cone with the cone metric is a Kähler manifold with Kähler form :t^2\,d\theta + 2t\,dt \cdot \theta. Examples As an example consider :S^\hookrightarrow ^=^ where the right hand side is a natural Kähler manifold and read as the cone over t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tohoku University
, or is a Japanese national university located in Sendai, Miyagi in the Tōhoku Region, Japan. It is informally referred to as . Established in 1907, it was the third Imperial University in Japan and among the first three Designated National Universities, along with the University of Tokyo and Kyoto University. Tohoku University is a Top Type university of the Top Global University Project, and since 2020 has been ranked the best university in Japan by Times Higher Education. In 2016, Tohoku University had 10 faculties, 16 graduate schools and 6 research institutes, with a total enrollment of 17,885 students. The university's three core values are "Research First (研究第一主義)," "Open-Doors (門戸開放)," and "Practice-Oriented Research and Education (実学尊重)." History On June 22, 1907(明治40年,''Mēji yonjyunen''), the university was established under the name by the Meiji government as the third Imperial University of Japan, following the Tokyo Imperi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tohoku Mathematical Journal
The ''Tohoku Mathematical Journal'' is a mathematical research journal published by Tohoku University in Japan. It was founded in August 1911 by Tsuruichi Hayashi. History Due to World War II the publication of the journal stopped in 1943 with volume 49. Publication was resumed in 1949 with the volume numbering starting again at 1. In order to distinguish between the identical numbered volumes, volumes in the first publishing period are referred to as the ''first series'' whereas the later volumes are called ''second series''. Before volume 51 of the second series the journal was called ''Tôhoku Mathematical Journal'', with a circumflex over the second letter of ''Tohoku''. Selected papers *. The first publication of the Sprague–Grundy theorem, the basis for much of combinatorial game theory, later independently rediscovered by P. M. Grundy. *. This paper describes Weiszfeld's algorithm for finding the geometric median. *. This paper, often referred to as " The Tohoku pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1912 Births
Year 191 ( CXCI) was a common year starting on Friday (link will display the full calendar) of the Julian calendar. At the time, it was known as the Year of the Consulship of Apronianus and Bradua (or, less frequently, year 944 ''Ab urbe condita''). The denomination 191 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years. Events By place Parthia * King Vologases IV of Parthia dies after a 44-year reign, and is succeeded by his son Vologases V. China * A coalition of Chinese warlords from the east of Hangu Pass launches a punitive campaign against the warlord Dong Zhuo, who seized control of the central government in 189, and held the figurehead Emperor Xian hostage. After suffering some defeats against the coalition forces, Dong Zhuo forcefully relocates the imperial capital from Luoyang to Chang'an. Before leaving, Dong Zhuo orders his troops to loot the tombs of the H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
