Biography:Michel Las Vergnas
Michel Las Vergnas | |
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| Born | 11 January 1941 Neuilly-sur-Seine, France |
| Died | 19 January 2013 (aged 72) Hauts-de-Seine, France |
| Education |
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| Known for |
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| Awards | CNRS Silver Medal (1986) |
| Scientific career | |
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| Institutions |
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| Thesis | Problèmes de couplages et problèmes hamiltoniens en théorie des graphes (1972) |
| Doctoral advisor | Claude Berge |
| Doctoral students | François Bry |
Michel Las Vergnas (11 January 1941 – 19 January 2013) was a French mathematician associated with Pierre-and-Marie-Curie University in Paris, and a research director emeritus at the Centre national de la recherche scientifique.[1][2]
Las Vergnas earned his Ph.D. in 1972 from Pierre-and-Marie-Curie University, under the supervision of Claude Berge.[3] He was one of the founders of the European Journal of Combinatorics, which began publishing in 1980.[4]
A workshop on combinatorial geometry, held in Marseille in April 2013, was dedicated to his memory.[5]
Research
Las Vergnas's early work was in graph theory, on matchings and connectivity.[1] From 1975 he was one of the pioneers of the theory of oriented matroids,[1][6][7] and with Robert G. Bland he wrote one of its founding papers;[8] his later work concerned connections between combinatorics and geometry.[1] In matroid theory he introduced the Tutte polynomial of a morphism of matroids, studied in a series of papers from the 1970s to 2013;[9] its specialisation to graphs embedded in surfaces is known as the Las Vergnas polynomial.[10] He also showed that matroids in general admit no tensor product.[11]
Conjectures
Several conjectures carry his name. The simplex conjecture, posed in 1980, states that every simple oriented matroid has a simplicial tope; it is known to hold for realizable oriented matroids and in rank three.[12][13]
The Cordovil–Las Vergnas conjecture, recorded by Roudneff and Sturmfels in 1988, states that any two uniform oriented matroids of the same rank on the same ground set are connected by a sequence of mutations; Roudneff and Sturmfels proved it for realizable oriented matroids.[14]
References
- ↑ 1.0 1.1 1.2 1.3 Michel Las Vergnas passed away , Equipe Combinatoire & Optimisation, Pierre-and-Marie-Curie University, retrieved 2013-11-03.
- ↑ Template:Deprecated archive at Pierre-and-Marie-Curie University, retrieved 2013-11-03.
- ↑ Michel Las Vergnas at the Mathematics Genealogy Project
- ↑ List of founding editors of Eur J. Comb, Elsevier, retrieved 2013-11-03.
- ↑ Workshop program, Combinatorial geometries: matroids, oriented matroids and applications, retrieved 2013-11-03.
- ↑ Oriented matroids, AMS Feature Column, Joseph Malkevitch, retrieved 2013-11-03.
- ↑ Björner, Anders; Las Vergnas, Michel; Sturmfels, Bernd; White, Neil; Ziegler, Günter (1999). Oriented Matroids. Encyclopedia of Mathematics and Its Applications. 46 (2nd ed.). Cambridge University Press. p. 150. ISBN 978-0-521-77750-6. https://books.google.com/books?id=k2an6eBxn3kC&pg=PA150.
- ↑ Bland, Robert G.; Las Vergnas, Michel (1978). "Orientability of matroids". Journal of Combinatorial Theory, Series B 24 (1): 94–123. doi:10.1016/0095-8956(78)90080-1.
- ↑ Las Vergnas, Michel (1999). "The Tutte polynomial of a morphism of matroids I. Set-pointed matroids and matroid perspectives". Annales de l'Institut Fourier 49 (3): 973–1015. doi:10.5802/aif.1702.
- ↑ Ellis-Monaghan, Joanna A.; Moffatt, Iain (2015). "The Las Vergnas polynomial for embedded graphs". European Journal of Combinatorics 50: 97–114. doi:10.1016/j.ejc.2015.03.017.
- ↑ Las Vergnas, Michel (1981). "On products of matroids". Discrete Mathematics 36 (1): 49–55. doi:10.1016/0012-365X(81)90172-4.
- ↑ Las Vergnas, Michel (1980). "Convexity in oriented matroids". Journal of Combinatorial Theory, Series B 29 (2): 231–243. doi:10.1016/0095-8956(80)90082-9.
- ↑ Knauer, Kolja; Marc, Tilen (2023). "Corners and simpliciality in oriented matroids and partial cubes". European Journal of Combinatorics 112: 103714. doi:10.1016/j.ejc.2023.103714.
- ↑ Roudneff, Jean-Pierre; Sturmfels, Bernd (1988). "Simplicial cells in arrangements and mutations of oriented matroids". Geometriae Dedicata 27 (2): 153–170. doi:10.1007/BF00151344.
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