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Combinatorial geometries: Matroids, oriented matroids and applications. Special issue in memory of Michel Las Vergnas
European Journal of Combinatorics 49 (2015) 269–270
Contents lists available at ScienceDirect
European Journal of Combinatorics journal homepage: www.elsevier.com/locate/ejc
Preface
Combinatorial geometries: Matroids, oriented matroids and applications. Special issue in memory of Michel Las Vergnas This special volume is dedicated to the memory of late Michel Las Vergnas who passed away on January 19, 2013 at age 72. Michel Las Vergnas was a combinatorial mathematician with artistic sense and creativity. He is also well known as a cofounder of the theory of oriented matroids which acquired the firm acceptance as fundamental concept in mathematics. Michel was one of the founding editors of European Journal of Combinatorics. On personal side, Michel had broad and deep interest in music, arts and culture. Michel was a warm-hearted individual caring for his family and friends with kind and genuine smiles. Michel was the first doctoral student of another great combinatorialist Claude Berge. They were two of the leaders of the Paris school of combinatorics (L’Equipe Combinatoire, Université Paris VI). They influenced greatly the advances of combinatorial mathematics in the world and guided many excellent graduate students. Both Claude and Michel had unusual talents to formulate beautiful conjectures. Throughout his whole career as Directeur de Recherche au CNRS and professor of University Pierre et Marie Curie (Paris 6), Michel’s devotion to combinatorial mathematics and to the guidance of doctoral students was extraordinary. The late Yahya Ould Hamidoune and the first editor Raul were the first doctoral students of Michel, graduated in 1978 and 1979, respectively. The third editor Emeric was the last student who completed his study in 2002. Michel had supervised 15 doctoral students. He won the silver medal of the CNRS in 1985. On his pioneering research front, Michel gave many equivalent axiomatizations of oriented matroids in an extensive manuscript,1 which unfortunately has never been fully published. Michel’s theorem on single-element extensions2 of oriented matroids turned out to be crucial in constructing fascinating examples and in resolving degeneracy in the abstract combinatorial setting of optimization. Michel had strong interest in a wide range of combinatorics beyond the oriented matroid theory, for instance, from ingenious generalizations of graph properties to binary matroids in his early works, to major contributions in understanding the power of the Tutte polynomial later, involving matroids, oriented matroids and morphisms of matroids, through enumerative, bijective and algebraic properties.
1 Michel Las Vergnas. Matroïdes orientables. unpublished monograph, April 1974. 2 Michel Las Vergnas. Extensions ponctuelles d’une géométrie combinatoire orientée. In Problèmes combinatoires et théorie des graphes (Colloq. Internat. CNRS, Univ. Orsay, Orsay, 1976), volume 260 of Colloq. Internat. CNRS, pages 265–270. CNRS, Paris, 1978. http://dx.doi.org/10.1016/j.ejc.2015.03.021 0195-6698/© 2015 Elsevier Ltd. All rights reserved.
270
Preface / European Journal of Combinatorics 49 (2015) 269–270
This special volume contains contributions which have been motivated directly or indirectly by the work and the vision of Michel Las Vergnas. The authors are from all over the world, ranging widely from junior to senior. Many of the papers were presented at the memorial conference for Michel ‘‘Combinatorial Geometries: matroids, oriented matroids and applications’’ held at CIRM, MarseilleLuminy, April 2–6, 2013,3 organized by Emeric and Jorge. Michel’s vast work and themes had and continue to have many followers. This volume is a clear witness of the invaluable gifts Michel Las Vergnas gave to all of us.
Michel Las Vergnas, February 2004 (Photo by Jorge Ramírez Alfonsín)
Raul Cordovil Departamento de Matematica Instituto Superior Tecnico, UL, Av. Rovisco Pai, 1049-001 Lisboa, Portugal Komei Fukuda Department of Mathematics, and Institute of Theoretical Computer Science, ETH Zurich (CAB G 33.3) Universitaetstrasse 6, CH-8092 Zurich, Switzerland Emeric Gioan Centre national de la recherche scientifique (CNRS), Laboratoire d’Informatique, de Robotique et de Microélectronique de Montpellier (LIRMM), Université de Montpellier, 161 Rue Ada, 34090 Montpellier, France Jorge Ramírez Alfonsín Institut de Mathématiques et de Modélisation de Montpellier, Université de Montpellier, Place Eugéne Bataillon, 34095 Montpellier, France Available online 16 May 2015
3 Partially supported by the TEOMATRO grant ANR-10-BLAN 0207.
Contents lists available at ScienceDirect
European Journal of Combinatorics journal homepage: www.elsevier.com/locate/ejc
Preface
Combinatorial geometries: Matroids, oriented matroids and applications. Special issue in memory of Michel Las Vergnas This special volume is dedicated to the memory of late Michel Las Vergnas who passed away on January 19, 2013 at age 72. Michel Las Vergnas was a combinatorial mathematician with artistic sense and creativity. He is also well known as a cofounder of the theory of oriented matroids which acquired the firm acceptance as fundamental concept in mathematics. Michel was one of the founding editors of European Journal of Combinatorics. On personal side, Michel had broad and deep interest in music, arts and culture. Michel was a warm-hearted individual caring for his family and friends with kind and genuine smiles. Michel was the first doctoral student of another great combinatorialist Claude Berge. They were two of the leaders of the Paris school of combinatorics (L’Equipe Combinatoire, Université Paris VI). They influenced greatly the advances of combinatorial mathematics in the world and guided many excellent graduate students. Both Claude and Michel had unusual talents to formulate beautiful conjectures. Throughout his whole career as Directeur de Recherche au CNRS and professor of University Pierre et Marie Curie (Paris 6), Michel’s devotion to combinatorial mathematics and to the guidance of doctoral students was extraordinary. The late Yahya Ould Hamidoune and the first editor Raul were the first doctoral students of Michel, graduated in 1978 and 1979, respectively. The third editor Emeric was the last student who completed his study in 2002. Michel had supervised 15 doctoral students. He won the silver medal of the CNRS in 1985. On his pioneering research front, Michel gave many equivalent axiomatizations of oriented matroids in an extensive manuscript,1 which unfortunately has never been fully published. Michel’s theorem on single-element extensions2 of oriented matroids turned out to be crucial in constructing fascinating examples and in resolving degeneracy in the abstract combinatorial setting of optimization. Michel had strong interest in a wide range of combinatorics beyond the oriented matroid theory, for instance, from ingenious generalizations of graph properties to binary matroids in his early works, to major contributions in understanding the power of the Tutte polynomial later, involving matroids, oriented matroids and morphisms of matroids, through enumerative, bijective and algebraic properties.
1 Michel Las Vergnas. Matroïdes orientables. unpublished monograph, April 1974. 2 Michel Las Vergnas. Extensions ponctuelles d’une géométrie combinatoire orientée. In Problèmes combinatoires et théorie des graphes (Colloq. Internat. CNRS, Univ. Orsay, Orsay, 1976), volume 260 of Colloq. Internat. CNRS, pages 265–270. CNRS, Paris, 1978. http://dx.doi.org/10.1016/j.ejc.2015.03.021 0195-6698/© 2015 Elsevier Ltd. All rights reserved.
270
Preface / European Journal of Combinatorics 49 (2015) 269–270
This special volume contains contributions which have been motivated directly or indirectly by the work and the vision of Michel Las Vergnas. The authors are from all over the world, ranging widely from junior to senior. Many of the papers were presented at the memorial conference for Michel ‘‘Combinatorial Geometries: matroids, oriented matroids and applications’’ held at CIRM, MarseilleLuminy, April 2–6, 2013,3 organized by Emeric and Jorge. Michel’s vast work and themes had and continue to have many followers. This volume is a clear witness of the invaluable gifts Michel Las Vergnas gave to all of us.
Michel Las Vergnas, February 2004 (Photo by Jorge Ramírez Alfonsín)
Raul Cordovil Departamento de Matematica Instituto Superior Tecnico, UL, Av. Rovisco Pai, 1049-001 Lisboa, Portugal Komei Fukuda Department of Mathematics, and Institute of Theoretical Computer Science, ETH Zurich (CAB G 33.3) Universitaetstrasse 6, CH-8092 Zurich, Switzerland Emeric Gioan Centre national de la recherche scientifique (CNRS), Laboratoire d’Informatique, de Robotique et de Microélectronique de Montpellier (LIRMM), Université de Montpellier, 161 Rue Ada, 34090 Montpellier, France Jorge Ramírez Alfonsín Institut de Mathématiques et de Modélisation de Montpellier, Université de Montpellier, Place Eugéne Bataillon, 34095 Montpellier, France Available online 16 May 2015
3 Partially supported by the TEOMATRO grant ANR-10-BLAN 0207.