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Rudolf Halin
Rudolf Halin (February 3, 1934 – November 14, 2014) was a German graph theory, graph theorist, known for defining the End (graph theory), ends of infinite graphs, for Halin's grid theorem, for extending Menger's theorem to infinite graphs, and for his early research on treewidth and tree decomposition. He is also the namesake of Halin graphs, a class of planar graphs constructed from tree (graph theory), trees by adding a cycle through the leaves of the given tree; earlier researchers had studied the subclass of cubic graph, cubic Halin graphs but Halin was the first to study this class of graphs in full generality. Life Halin was born on February 3, 1934 in Uerdingen.. Date corrected in a follow-up email from Diestel. Birthplace from his books ''Graphentheorie I, II''. He earned his doctorate from the University of Cologne in 1962, under the supervision of Klaus Wagner and Karl Dörge, after which he joined the faculty of the University of Hamburg. He died on November 14, 2014, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graph Theory
In mathematics, graph theory is the study of ''graphs'', which are mathematical structures used to model pairwise relations between objects. A graph in this context is made up of '' vertices'' (also called ''nodes'' or ''points'') which are connected by '' edges'' (also called ''links'' or ''lines''). A distinction is made between undirected graphs, where edges link two vertices symmetrically, and directed graphs, where edges link two vertices asymmetrically. Graphs are one of the principal objects of study in discrete mathematics. Definitions Definitions in graph theory vary. The following are some of the more basic ways of defining graphs and related mathematical structures. Graph In one restricted but very common sense of the term, a graph is an ordered pair G=(V,E) comprising: * V, a set of vertices (also called nodes or points); * E \subseteq \, a set of edges (also called links or lines), which are unordered pairs of vertices (that is, an edge is associated with t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Klaus Wagner
Klaus Wagner (March 31, 1910 – February 6, 2000) was a German mathematician known for his contributions to graph theory. Education and career Wagner studied topology at the University of Cologne under the supervision of who had been a student of Issai Schur. Wagner received his Ph.D. in 1937, with a dissertation concerning the Jordan curve theorem and four color theorem, and taught at Cologne for many years himself. In 1970, he moved to the University of Duisburg, where he remained until his retirement in 1978. Graph minors Wagner is known for his contributions to graph theory and particularly the theory of graph minors, graphs that can be formed from a larger graph by contracting and removing edges. Wagner's theorem characterizes the planar graphs as exactly those graphs that do not have as a minor either a complete graph ''K''5 on five vertices or a complete bipartite graph ''K''3,3 with three vertices on each side of its bipartition. That is, these two graphs are the onl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graph Theorists
Graph may refer to: Mathematics *Graph (discrete mathematics), a structure made of vertices and edges **Graph theory, the study of such graphs and their properties *Graph (topology), a topological space resembling a graph in the sense of discrete mathematics * Graph of a function *Graph of a relation *Graph paper *Chart, a means of representing data (also called a graph) Computing * Graph (abstract data type), an abstract data type representing relations or connections *graph (Unix), Unix command-line utility *Conceptual graph, a model for knowledge representation and reasoning Other uses * HMS ''Graph'', a submarine of the UK Royal Navy See also *Complex network *Graf *Graff (other) *Graph database *Grapheme, in linguistics *Graphemics *Graphic (other) *-graphy (suffix from the Greek for "describe," "write" or "draw") *List of information graphics software This is a list of software to create any kind of information graphics: * either includes the ability t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2014 Deaths
This is a list of deaths of notable people, organised by year. New deaths articles are added to their respective month (e.g., Deaths in ) and then linked here. 2022 2021 2020 2019 2018 2017 2016 2015 2014 2013 2012 2011 2010 2009 2008 2007 2006 2005 2004 2003 2002 2001 2000 1999 1998 1997 1996 1995 1994 1993 1992 1991 1990 1989 1988 1987 See also * Lists of deaths by day The following pages, corresponding to the Gregorian calendar, list the historical events, births, deaths, and holidays and observances of the specified day of the year: Footnotes See also * Leap year * List of calendars * List of non-standard ... * Deaths by year {{DEFAULTSORT:deaths by year ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1934 Births
Events January–February * January 1 – The International Telecommunication Union, a specialist agency of the League of Nations, is established. * January 15 – The 8.0 Nepal–Bihar earthquake strikes Nepal and Bihar with a maximum Mercalli intensity of XI (''Extreme''), killing an estimated 6,000–10,700 people. * January 26 – A 10-year German–Polish declaration of non-aggression is signed by Nazi Germany and the Second Polish Republic. * January 30 ** In Nazi Germany, the political power of federal states such as Prussia is substantially abolished, by the "Law on the Reconstruction of the Reich" (''Gesetz über den Neuaufbau des Reiches''). ** Franklin D. Roosevelt, President of the United States, signs the Gold Reserve Act: all gold held in the Federal Reserve is to be surrendered to the United States Department of the Treasury; immediately following, the President raises the statutory gold price from US$20.67 per ounce to $35. * February 6 – F ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematische Nachrichten
''Mathematische Nachrichten'' (abbreviated ''Math. Nachr.''; English: ''Mathematical News'') is a mathematical journal published in 12 issues per year by Wiley-VCH GmbH. It should not be confused with the ''Internationale Mathematische Nachrichten'', an unrelated publication of the Austrian Mathematical Society. It was established in 1948 by East German mathematician Erhard Schmidt, who became its first editor-in-chief. At that time it was associated with the German Academy of Sciences at Berlin, and published by Akademie Verlag. After the fall of the Berlin Wall, Akademie Verlag was sold to VCH Verlagsgruppe Weinheim, which in turn was sold to John Wiley & Sons. According to the 2020 edition of Journal Citation Reports, the journal had an impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a scientometric index calculated by Clarivate that reflects the yearly mean number of citations of articles published in the last two years in a g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mathematische Annalen
''Mathematische Annalen'' (abbreviated as ''Math. Ann.'' or, formerly, ''Math. Annal.'') is a German mathematical research journal founded in 1868 by Alfred Clebsch and Carl Neumann. Subsequent managing editors were Felix Klein, David Hilbert, Otto Blumenthal, Erich Hecke, Heinrich Behnke, Hans Grauert, Heinz Bauer, Herbert Amann, Jean-Pierre Bourguignon, Wolfgang Lück, and Nigel Hitchin. Currently, the managing editor of Mathematische Annalen is Thomas Schick. Volumes 1–80 (1869–1919) were published by Teubner. Since 1920 (vol. 81), the journal has been published by Springer. In the late 1920s, under the editorship of Hilbert, the journal became embroiled in controversy over the participation of L. E. J. Brouwer on its editorial board, a spillover from the foundational Brouwer–Hilbert controversy. Between 1945 and 1947 the journal briefly ceased publication. References External links''Mathematische Annalen''homepage at Springer''Mathematische Annalen''archive (1869†... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mölln, Schleswig-Holstein
Mölln () is a town in Schleswig-Holstein, Germany. It is surrounded by several small lakes (Stadtsee, Schulsee, Ziegelsee, Hegesee, Schmalsee, Lütauer See, Drüsensee, and Pinnsee). The Elbe-Lübeck Canal flows through the town. Mölln belongs to the district of Herzogtum Lauenburg. History The town was founded in the 12th century. It rapidly became an important town, due to the Old Salt Route, through which the salt produced in the salt mines of Lüneburg (Lower-Saxony) was shipped to the Baltic harbour of Lübeck, and the Stecknitz Canal, which was a precursor of today's Elbe-Lübeck Canal. Although situated in the midst of the medieval duchy of Lauenburg, the town was mortgaged to the Hanseatic town of Lübeck, which ruled Mölln from 1359 to 1683. Back from this time dates the Möllner Schützengilde von 1407 e.V. which was founded over 600 years ago and still exists today with almost 300 members. Mölln calls itself the Eulenspiegel town, because of Till Eulenspi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Hamburg
The University of Hamburg (german: link=no, Universität Hamburg, also referred to as UHH) is a public research university in Hamburg, Germany. It was founded on 28 March 1919 by combining the previous General Lecture System ('' Allgemeines Vorlesungswesen''), the Hamburg Colonial Institute ('' Hamburgisches Kolonialinstitut''), and the Academic College ('' Akademisches Gymnasium''). The main campus is located in the central district of Rotherbaum, with affiliated institutes and research centres distributed around the city-state. The university has been ranked in the top 200 universities worldwide by the ''Times Higher Education Ranking'', the Shanghai Ranking and the CWTS Leiden Ranking, placing it among the top 1% of global universities. Seven Nobel Prize winners and one Wolf Prize winner are affiliated with UHH. On a national scale, '' U.S. News & World Report'' ranks UHH 7th and ''QS World University Rankings'' 14th out of a total of 426 German institutions of higher educa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Cologne
The University of Cologne (german: Universität zu Köln) is a university in Cologne, Germany. It was established in the year 1388 and is one of the most prestigious and research intensive universities in Germany. It was the sixth university to be established in Central Europe. It closed in 1798 before being re-established in 1919. It is now one of the largest universities in Germany with more than 48,000 students. The University of Cologne was a university of excellence as part of the German Universities Excellence Initiative from 2012 to 2019. As of 2021, 3 Nobel Prize winners have been affiliated with the university. Professors and former students have won 11 Leibniz Prizes, the most prestigious as well as the best-funded prize in Europe. History 1388–1798 The university of Cologne was established in 1388 as the fourth university in the Holy Roman Empire, after the Charles University of Prague (1348), the University of Vienna (1365) and the Ruprecht Karl University of H ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
End (graph Theory)
In the mathematics of infinite graphs, an end of a graph represents, intuitively, a direction in which the graph extends to infinity. Ends may be formalized mathematically as equivalence classes of infinite paths, as havens describing strategies for pursuit–evasion games on the graph, or (in the case of locally finite graphs) as topological ends of topological spaces associated with the graph. Ends of graphs may be used (via Cayley graphs) to define ends of finitely generated groups. Finitely generated infinite groups have one, two, or infinitely many ends, and the Stallings theorem about ends of groups provides a decomposition for groups with more than one end. Definition and characterization Ends of graphs were defined by in terms of equivalence classes of infinite paths. A in an infinite graph is a semi-infinite simple path; that is, it is an infinite sequence of vertices v_0,v_1,v_2,\dots in which each vertex appears at most once in the sequence and each two consecutive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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