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Regina (program)
Regina is a suite of mathematical software for 3-manifold topology, topologists. It focuses upon the study of 3-manifold Triangulation (topology), triangulations and includes support for normal surfaces and angle structures. Features * Regina implements a variant of Hyam Rubinstein, Rubinstein's 3-sphere recognition algorithm. This is an algorithm that determines whether or not a Triangulation (topology), triangulated 3-manifold is homeomorphism, homeomorphic to the 3-sphere. * Regina further implements the connected sum, connect-sum decomposition. This will decompose a triangulation (topology), triangulated 3-manifold into a connected sum, connect-sum of triangulation (topology), triangulated connected sum, prime 3-manifolds. * Simplicial homology, Homology and Poincare duality for 3-manifolds, including the Poincare duality, torsion linking form. * Includes portions of the SnapPea, SnapPea kernel for some geometric calculations. * Has both a GUI and Python (programming lang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Normal Surface
In mathematics, a normal surface is a Surface (topology), surface inside a triangulated 3-manifold that intersects each tetrahedron in several components called normal disks. Each normal disk is either a ''triangle'' which cuts off a vertex of the tetrahedron, or a ''quadrilateral'' which separates pairs of vertices. In a given tetrahedron there cannot be two quadrilaterals separating different pairs of vertices, since such quadrilaterals would intersect in a line, causing the surface to be self-intersecting. Dually, a normal surface can be considered as a surface that intersects each handle of a given handle structure on the 3-manifold in a prescribed manner, similar to the above. The concept of a normal surface can be generalized to arbitrary polyhedra. There are also related notions of almost normal surfaces and spun normal surfaces. In an almost normal surface, one tetrahedron in the triangulation has a single exceptional piece. This is either an ''octagon'' that separates p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
3-sphere
In mathematics, a hypersphere or 3-sphere is a 4-dimensional analogue of a sphere, and is the 3-dimensional n-sphere, ''n''-sphere. In 4-dimensional Euclidean space, it is the set of points equidistant from a fixed central point. The interior of a 3-sphere is a 4-ball. It is called a 3-sphere because topologically, the surface itself is 3-dimensional, even though it is curved into the 4th dimension. For example, when traveling on a 3-sphere, you can go north and south, east and west, or along a 3rd set of cardinal directions. This means that a 3-sphere is an example of a 3-manifold. Definition In coordinates, a 3-sphere with center and radius is the set of all points in real, Four-dimensional space, 4-dimensional space () such that :\sum_^3(x_i - C_i)^2 = ( x_0 - C_0 )^2 + ( x_1 - C_1 )^2 + ( x_2 - C_2 )^2+ ( x_3 - C_3 )^2 = r^2. The 3-sphere centered at the origin with radius 1 is called the unit 3-sphere and is usually denoted : :S^3 = \left\. It is often convenient to r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computational Topology
Algorithmic topology, or computational topology, is a subfield of topology with an overlap with areas of computer science, in particular, computational geometry and computational complexity theory. A primary concern of algorithmic topology, as its name suggests, is to develop efficient algorithms for solving problems that arise naturally in fields such as computational geometry, graphics, robotics, social science, structural biology, and chemistry, using methods from computable topology. Major algorithms by subject area Algorithmic 3-manifold theory A large family of algorithms concerning 3-manifolds revolve around normal surface theory, which is a phrase that encompasses several techniques to turn problems in 3-manifold theory into integer linear programming problems. * ''Rubinstein and Thompson's 3-sphere recognition algorithm''. This is an algorithm that takes as input a triangulated 3-manifold and determines whether or not the manifold is homeomorphic to the 3-sphere. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SnapPea
SnapPea is free software designed to help mathematicians, in particular low-dimensional topologists, study hyperbolic 3-manifolds. The primary developer is Jeffrey Weeks, who created the first version as part of his doctoral thesis, supervised by William Thurston. It is not to be confused with the unrelated Android malware with the same name. The latest version is 3.0d3. Marc Culler, Nathan Dunfield and collaborators have extended the SnapPea kernel and written Python extension modules which allow the kernel to be used in a Python program or in the interpreter. They also provide a graphical user interface written in Python which runs under most operating systems (see external links below). The following people are credited in SnapPea 2.5.3's list of acknowledgments: Colin Adams, Bill Arveson, Pat Callahan, Joe Christy, Dave Gabai, Charlie Gunn, Martin Hildebrand, Craig Hodgson, Diane Hoffoss, A. C. Manoharan, Al Marden, Dick McGehee, Rob Meyerhoff, Lee Moshe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Simplicial Homology
In algebraic topology, simplicial homology is the sequence of homology groups of a simplicial complex. It formalizes the idea of the number of holes of a given dimension in the complex. This generalizes the number of connected component (topology), connected components (the case of dimension 0). Simplicial homology arose as a way to study topological spaces whose building blocks are ''n''-simplices, the ''n''-dimensional analogs of triangles. This includes a point (0-simplex), a line segment (1-simplex), a triangle (2-simplex) and a tetrahedron (3-simplex). By definition, such a space is homeomorphic to a simplicial complex (more precisely, the abstract simplicial complex, geometric realization of an abstract simplicial complex). Such a homeomorphism is referred to as a ''Triangulation (topology), triangulation'' of the given space. Many topological spaces of interest can be triangulated, including every smooth manifold (Cairns and J.H.C. Whitehead, Whitehead). Simplicial homology ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangulation (topology)
In mathematics, triangulation describes the replacement of topological spaces with simplicial complexes by the choice of an appropriate homeomorphism. A space that admits such a homeomorphism is called a triangulable space. Triangulations can also be used to define a piecewise linear structure for a space, if one exists. Triangulation has various applications both in and outside of mathematics, for instance in algebraic topology, in complex analysis, and in modeling. Motivation On the one hand, it is sometimes useful to forget about superfluous information of topological spaces: The replacement of the original spaces with simplicial complexes may help to recognize crucial properties and to gain a better understanding of the considered object. On the other hand, simplicial complexes are objects of combinatorial character and therefore one can assign them quantities arising from their combinatorial pattern, for instance, the Euler characteristic. Triangulation allows now to as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Connected Sum
In mathematics, specifically in topology, the operation of connected sum is a geometric modification on manifolds. Its effect is to join two given manifolds together near a chosen point on each. This construction plays a key role in the classification of closed surfaces. More generally, one can also join manifolds together along identical submanifolds; this generalization is often called the fiber sum. There is also a closely related notion of a connected sum on knots, called the knot sum or composition of knots. Connected sum at a point A connected sum of two ''m''-dimensional manifolds is a manifold formed by deleting a ball inside each manifold and gluing together the resulting boundary spheres. If both manifolds are oriented, there is a unique connected sum defined by having the gluing map reverse orientation. Although the construction uses the choice of the balls, the result is unique up to homeomorphism. One can also make this operation work in the smooth categor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homeomorphism
In mathematics and more specifically in topology, a homeomorphism ( from Greek roots meaning "similar shape", named by Henri Poincaré), also called topological isomorphism, or bicontinuous function, is a bijective and continuous function between topological spaces that has a continuous inverse function. Homeomorphisms are the isomorphisms in the category of topological spaces—that is, they are the mappings that preserve all the topological properties of a given space. Two spaces with a homeomorphism between them are called homeomorphic, and from a topological viewpoint they are the same. Very roughly speaking, a topological space is a geometric object, and a homeomorphism results from a continuous deformation of the object into a new shape. Thus, a square and a circle are homeomorphic to each other, but a sphere and a torus are not. However, this description can be misleading. Some continuous deformations do not produce homeomorphisms, such as the deformation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Regina Logo
Regina (Latin for "queen") may refer to: Places Canada * Regina, Saskatchewan, the capital city of the province ** Regina (electoral district) ** Roman Catholic Archdiocese of Regina France * Régina, French Guiana, a commune United States * Regina, Minneapolis, Minnesota, a neighborhood * Regina, Missouri, an unincorporated community * Regina, New Mexico, a census-designated place * Regina, Virginia, an unincorporated community * Regina, Wisconsin, an unincorporated community People *Regina (given name) * Regina (name) * Regina (concubine), 8th century French concubine of Charlemagne * Regina (martyr) (died 251 or 286), French martyr * Regina (American singer), American singer Regina Marie Cuttita () *Regina (Slovenian singer), Slovenian singer born Irena Jalšovec (born 1965) * Regina "Queen" Saraiva (born 1968), Eurodance singer with the stage name Regina Films * ''Regina'' (1987 film), an Italian drama film * ''Regina'' (1989 film), an Estonian film * ''Regina'' (2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyam Rubinstein
Joachim Hyam Rubinstein FAA (born 7 March 1948, in Melbourne) an Australian top mathematician specialising in low-dimensional topology; he is currently serving as an honorary professor in the Department of Mathematics and Statistics at the University of Melbourne, having retired in 2019. He has spoken and written widely on the state of the mathematical sciences in Australia, with particular focus on the impacts of reduced Government spending for university mathematics departments. Education In 1965, Rubinstein matriculated (i.e. graduated) from Melbourne High School in Melbourne, Australia winning the maximum of four exhibitions. In 1969, he graduated from Monash University in Melbourne, with a B.Sc.(Honours) degree in mathematics. In 1974, Rubinstein received his Ph.D. from the University of California, Berkeley under the advisership of John Stallings. His dissertation was on the topic of ''Isotopies of Incompressible Surfaces in Three Dimensional Manifolds''. Researc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Triangulation (topology)
In mathematics, triangulation describes the replacement of topological spaces with simplicial complexes by the choice of an appropriate homeomorphism. A space that admits such a homeomorphism is called a triangulable space. Triangulations can also be used to define a piecewise linear structure for a space, if one exists. Triangulation has various applications both in and outside of mathematics, for instance in algebraic topology, in complex analysis, and in modeling. Motivation On the one hand, it is sometimes useful to forget about superfluous information of topological spaces: The replacement of the original spaces with simplicial complexes may help to recognize crucial properties and to gain a better understanding of the considered object. On the other hand, simplicial complexes are objects of combinatorial character and therefore one can assign them quantities arising from their combinatorial pattern, for instance, the Euler characteristic. Triangulation allows now to as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
