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Borsuk's Conjecture
The Borsuk problem in geometry, for historical reasons incorrectly called Borsuk's conjecture, is a question in discrete geometry. It is named after Karol Borsuk. Problem In 1932, Karol Borsuk showed that an ordinary 3-dimensional ball in Euclidean space can be easily dissected into 4 solids, each of which has a smaller diameter than the ball, and generally ''n''-dimensional ball can be covered with compact sets of diameters smaller than the ball. At the same time he proved that ''n'' subsets are not enough in general. The proof is based on the Borsuk–Ulam theorem. That led Borsuk to a general question: : ''Die folgende Frage bleibt offen: Lässt sich jede beschränkte Teilmenge E des Raumes \mathbb R^n in'' (''n'' + 1) ''Mengen zerlegen, von denen jede einen kleineren Durchmesser als E hat?'' This can be translated as: : ''The following question remains open: Can every bounded Boundedness or bounded may refer to: Economics * Bounded rationality, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borsuk Hexagon
{{disambiguation, geo, surname ...
Borsuk (the word for "badger" in a number of Slavic languages) may refer to: *Angela Borsuk (born 1967), Israeli chess player *Karol Borsuk, Polish mathematician *Borsuk, Hrubieszów County in Lublin Voivodeship (east Poland) *Borsuk, Krasnystaw County in Lublin Voivodeship (east Poland) * Borsuk IFV, a Polish IFV made by Huta Stalowa Wola Huta Stalowa Wola (HSW SA) is a defense contractor that operates a steel mill in the city of Stalowa Wola, Poland. It is a major producer of military equipment and one of the largest heavy construction machinery producers in East-Central Euro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hugo Hadwiger
Hugo Hadwiger (23 December 1908 in Karlsruhe, Germany – 29 October 1981 in Bern, Switzerland) was a Swiss mathematician, known for his work in geometry, combinatorics, and cryptography. Biography Although born in Karlsruhe, Germany, Hadwiger grew up in Bern, Switzerland.. He did his undergraduate studies at the University of Bern, where he majored in mathematics but also studied physics and actuarial science. He continued at Bern for his graduate studies, and received his Ph.D. in 1936 under the supervision of Willy Scherrer. He was for more than forty years a professor of mathematics at Bern. Mathematical concepts named after Hadwiger Hadwiger's theorem in integral geometry classifies the isometry-invariant valuations on compact convex sets in ''d''-dimensional Euclidean space. According to this theorem, any such valuation can be expressed as a linear combination of the intrinsic volumes; for instance, in two dimensions, the intrinsic volumes are the area, the perime ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kahn–Kalai Conjecture
The Kahn–Kalai conjecture, also known as the expectation threshold conjecture, is a conjecture in the field of graph theory and statistical mechanics, proposed by Jeff Kahn and Gil Kalai in 2006. Background This conjecture concerns the general problem of estimating when phase transitions occur in systems. For example, in a random network with N nodes, where each edge is included with probability p, it is unlikely for the graph to contain a Hamiltonian cycle if p is less than a threshold value (\log N)/N, but highly likely if p exceeds that threshold. Threshold values are often difficult to calculate, but a lower bound for the threshold, the "expectation threshold", is generally easier to calculate. The Kahn–Kalai conjecture is that the two values are generally close together in a precisely defined way, namely that there is a universal constant A physical constant, sometimes fundamental physical constant or universal constant, is a physical quantity that is generally ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hadwiger Conjecture (combinatorial Geometry)
In combinatorial geometry, the Hadwiger conjecture states that any convex body in ''n''-dimensional Euclidean space can be covered by 2''n'' or fewer smaller bodies homothetic with the original body, and that furthermore, the upper bound of 2''n'' is necessary if and only if the body is a parallelepiped. There also exists an equivalent formulation in terms of the number of floodlights needed to illuminate the body. The Hadwiger conjecture is named after Hugo Hadwiger, who included it on a list of unsolved problems in 1957; it was, however, previously studied by and independently, . Additionally, there is a different Hadwiger conjecture concerning graph coloring—and in some sources the geometric Hadwiger conjecture is also called the Levi–Hadwiger conjecture or the Hadwiger–Levi covering problem. The conjecture remains unsolved even in three dimensions, though the two dimensional case was resolved by . Formal statement Formally, the Hadwiger conjecture is: If ''K'' is any ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematika
''Mathematika'' is a peer-reviewed mathematics journal that publishes both pure and applied mathematical articles. The journal was founded by Harold Davenport in the 1950s. The journal is published by the London Mathematical Society, on behalf of the journal's owner University College London. Indexing and abstracting According to the ''Journal Citation Reports'', the journal has a 2020 impact factor of 0.844. The journal in indexing in the following bibliographic databases: * MathSciNet * Science Citation Index Expanded * Web of Science * Zentralblatt MATH zbMATH Open, formerly Zentralblatt MATH, is a major reviewing service providing reviews and abstracts for articles in pure and applied mathematics, produced by the Berlin office of FIZ Karlsruhe – Leibniz Institute for Information Infrastruct ... References {{reflist London Mathematical Society Mathematics education in the United Kingdom Mathematics journals Publications established in 1954 Quarterly journals Wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oded Schramm
Oded Schramm ( he, עודד שרם; December 10, 1961 – September 1, 2008) was an Israeli-American mathematician known for the invention of the Schramm–Loewner evolution (SLE) and for working at the intersection of conformal field theory and probability theory. Biography Schramm was born in Jerusalem. His father, Michael Schramm, was a biochemistry professor at the Hebrew University of Jerusalem. He attended Hebrew University, where he received his bachelor's degree in mathematics and computer science in 1986 and his master's degree in 1987, under the supervision of Gil Kalai. He then received his PhD from Princeton University in 1990 under the supervision of William Thurston. After receiving his doctorate, he worked for two years at the University of California, San Diego, and then had a permanent position at the Weizmann Institute from 1992 to 1999. In 1999 he moved to the Theory Group at Microsoft Research in Redmond, Washington, where he remained for the rest of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronic Journal Of Combinatorics
The ''Electronic Journal of Combinatorics'' is a peer-reviewed open access scientific journal covering research in combinatorial mathematics. The journal was established in 1994 by Herbert Wilf (University of Pennsylvania) and Neil Calkin (Georgia Institute of Technology). The Electronic Journal of Combinatorics is a founding member of the Free Journal Network. According to the ''Journal Citation Reports'', the journal had a 2017 impact factor of 0.762. Editors-in-chief Current The current editors-in-chief are: * Maria Axenovich, Karlsruhe Institute of Technology, Germany * Miklós Bóna, University of Florida, United States * Julia Böttcher, London School of Economics, United Kingdom * Richard A. Brualdi, University of Wisconsin, Madison, United States * Eric Fusy, CNRS/LIX, École Polytechnique, France * Catherine Greenhill, UNSW Sydney, Australia * Brendan McKay, Australian National University, Australia * Bojan Mohar, Simon Fraser University, Canada * Marc Noy, Unive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Discrete & Computational Geometry
'' Discrete & Computational Geometry'' is a peer-reviewed mathematics journal published quarterly by Springer. Founded in 1986 by Jacob E. Goodman and Richard M. Pollack, the journal publishes articles on discrete geometry and computational geometry. Abstracting and indexing The journal is indexed in: * ''Mathematical Reviews'' * ''Zentralblatt MATH'' * ''Science Citation Index The Science Citation Index Expanded – previously entitled Science Citation Index – is a citation index originally produced by the Institute for Scientific Information (ISI) and created by Eugene Garfield. It was officially launched in 1964 ...'' * '' Current Contents''/Engineering, Computing and Technology Notable articles The articles by Gil Kalai with a proof of a subexponential upper bound on the diameter of a polyhedron and by Samuel Ferguson on the Kepler conjecture, both published in Discrete & Computational geometry, earned their author the Fulkerson Prize. References Externa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bulletin Of The American Mathematical Society
The ''Bulletin of the American Mathematical Society'' is a quarterly mathematical journal published by the American Mathematical Society. Scope It publishes surveys on contemporary research topics, written at a level accessible to non-experts. It also publishes, by invitation only, book reviews and short ''Mathematical Perspectives'' articles. History It began as the ''Bulletin of the New York Mathematical Society'' and underwent a name change when the society became national. The Bulletin's function has changed over the years; its original function was to serve as a research journal for its members. Indexing The Bulletin is indexed in Mathematical Reviews ''Mathematical Reviews'' is a journal published by the American Mathematical Society (AMS) that contains brief synopses, and in some cases evaluations, of many articles in mathematics, statistics, and theoretical computer science. The AMS also ..., Science Citation Index, ISI Alerting Services, CompuMath Citation Ind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gil Kalai
Gil Kalai (born 1955) is the Henry and Manya Noskwith Professor Emeritus of Mathematics at the Hebrew University of Jerusalem, Israel, Professor of Computer Science at the Interdisciplinary Center, Herzliya, and adjunct Professor of mathematics and of computer science at Yale University, United States. Biography Kalai received his PhD from Hebrew University in 1983, under the supervision of Micha Perles, and joined the Hebrew University faculty in 1985 after a postdoctoral fellowship at the Massachusetts Institute of Technology.Profile at the Technical University of Eindhoven as an instructor of a minicourse on polyhedral combinatorics. He was the recipient of the Pólya Prize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jeff Kahn
Jeffry Ned Kahn is a professor of mathematics at Rutgers University notable for his work in combinatorics. Education Kahn received his Ph.D. from Ohio State University in 1979 after completing his dissertation under his advisor Dijen K. Ray-Chaudhuri. Research In 1980 he showed the importance of the bundle theorem for ovoidal Möbius planes. In 1993, together with Gil Kalai, he disproved Borsuk's conjecture. In 1996 he was awarded the Pólya Prize (SIAM). Awards and honors He was an invited speaker at the 1994 International Congress of Mathematicians in Zurich. In 2012, he was awarded the Fulkerson Prize (jointly with Anders Johansson and Van H. Vu) for determining the threshold of edge density above which a random graph can be covered by disjoint copies of a given smaller graph. Also in 2012, he became a fellow of the American Mathematical Society The American Mathematical Society (AMS) is an association of professional mathematicians dedicated to the interests of mat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid Of Revolution
In geometry, a solid of revolution is a solid figure obtained by rotating a plane figure around some straight line (the '' axis of revolution'') that lies on the same plane. The surface created by this revolution and which bounds the solid is the surface of revolution. Assuming that the curve does not cross the axis, the solid's volume is equal to the length of the circle described by the figure's centroid multiplied by the figure's area ( Pappus's second centroid theorem). A representative disc is a three-dimensional volume element of a solid of revolution. The element is created by rotating a line segment (of length ) around some axis (located units away), so that a cylindrical volume of units is enclosed. Finding the volume Two common methods for finding the volume of a solid of revolution are the disc method and the shell method of integration. To apply these methods, it is easiest to draw the graph in question; identify the area that is to be revolved about the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
