Bojan Mohar (born September 21, 1956) is a Slovenian and Canadian mathematician, working in graph theory. He is a professor of mathematics at the University of Ljubljana [1] and the holder of a Canada Research Chair in graph theory at Simon Fraser University in Vancouver, British Columbia, Canada. [2]
Mohar received his PhD from the University of Ljubljana in 1986, under the supervision of Tomo Pisanski. [3]
Mohar's research concerns topological graph theory, algebraic graph theory, graph minors, and graph coloring. [2]
With Carsten Thomassen he is the co-author of the book Graphs on Surfaces (Johns Hopkins University Press, 2001).
Mohar was a Fulbright visiting scholar at Ohio State University in 1988, and won the Boris Kidrič prize of the Socialist Republic of Slovenia in 1990. [4] He has been a member of the Slovenian Academy of Engineering since 1999. [4] He was named a SIAM Fellow in 2018. [5] He was elected as a Fellow of the American Mathematical Society in the 2020 Class, for "contributions to topological graph theory, including the theory of graph embedding algorithms, graph coloring and crossing numbers, and for service to the profession". [6]
Discrete mathematics is the study of mathematical structures that can be considered "discrete" rather than "continuous". Objects studied in discrete mathematics include integers, graphs, and statements in logic. By contrast, discrete mathematics excludes topics in "continuous mathematics" such as real numbers, calculus or Euclidean geometry. Discrete objects can often be enumerated by integers; more formally, discrete mathematics has been characterized as the branch of mathematics dealing with countable sets. However, there is no exact definition of the term "discrete mathematics".
Tomaž (Tomo) Pisanski is a Slovenian mathematician working mainly in discrete mathematics and graph theory. He is considered by many Slovenian mathematicians to be the "father of Slovenian discrete mathematics."
Dušan D. Repovš is a Slovenian mathematician from Ljubljana, Slovenia.
George Neil Robertson is a mathematician working mainly in topological graph theory, currently a distinguished professor emeritus at the Ohio State University.
In combinatorial mathematics, rotation systems encode embeddings of graphs onto orientable surfaces by describing the circular ordering of a graph's edges around each vertex. A more formal definition of a rotation system involves pairs of permutations; such a pair is sufficient to determine a multigraph, a surface, and a 2-cell embedding of the multigraph onto the surface.
In the mathematical field of graph theory, Fáry's theorem states that any simple, planar graph can be drawn without crossings so that its edges are straight line segments. That is, the ability to draw graph edges as curves instead of as straight line segments does not allow a larger class of graphs to be drawn. The theorem is named after István Fáry, although it was proved independently by Klaus Wagner, Fáry, and Sherman K. Stein.
Carsten Thomassen is a Danish mathematician. He has been a Professor of Mathematics at the Technical University of Denmark since 1981, and since 1990 a member of the Royal Danish Academy of Sciences and Letters. His research concerns discrete mathematics and more specifically graph theory.
In topological graph theory, an embedding of a graph on a surface is a representation of on in which points of are associated with vertices and simple arcs are associated with edges in such a way that:
Mihalis Yannakakis is professor of computer science at Columbia University. He is noted for his work in computational complexity, databases, and other related fields. He won the Donald E. Knuth Prize in 2005.
In the mathematical field of graph theory, a graph G is said to be hypohamiltonian if G itself does not have a Hamiltonian cycle but every graph formed by removing a single vertex from G is Hamiltonian.
Heiko Harborth is Professor of Mathematics at Braunschweig University of Technology, 1975–present, and author of more than 188 mathematical publications. His work is mostly in the areas of number theory, combinatorics and discrete geometry, including graph theory.
Robin Thomas was a mathematician working in graph theory at the Georgia Institute of Technology.
In the mathematical field of graph theory, Grötzsch's theorem is the statement that every triangle-free planar graph can be colored with only three colors. According to the four-color theorem, every graph that can be drawn in the plane without edge crossings can have its vertices colored using at most four different colors, so that the two endpoints of every edge have different colors, but according to Grötzsch's theorem only three colors are needed for planar graphs that do not contain three mutually adjacent vertices.
In graph theory, a branch of mathematics, an apex graph is a graph that can be made planar by the removal of a single vertex. The deleted vertex is called an apex of the graph. It is an apex, not the apex because an apex graph may have more than one apex; for example, in the minimal nonplanar graphs K5 or K3,3, every vertex is an apex. The apex graphs include graphs that are themselves planar, in which case again every vertex is an apex. The null graph is also counted as an apex graph even though it has no vertex to remove.
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 as topological ends of topological spaces associated with the graph.
Bruce Alan ReedFRSC is a Canadian mathematician and computer scientist, a former Canada Research Chair in Graph Theory at McGill University. His research is primarily in graph theory. He is a distinguished research fellow of the Institute of Mathematics in the Academia Sinica, Taiwan, and an adjunct professor at the University of Victoria in Canada.
Thomas William Tucker is an American mathematician, the Charles Hetherington Professor of Mathematics at Colgate University, and an expert in the area of topological graph theory.
Daniel Kráľ is a Czech mathematician and computer scientist who works as a professor of mathematics and computer science at the Masaryk University. His research primarily concerns graph theory and graph algorithms.
In graph theory, precoloring extension is the problem of extending a graph coloring of a subset of the vertices of a graph, with a given set of colors, to a coloring of the whole graph that does not assign the same color to any two adjacent vertices.
Dan Steven Archdeacon (1954–2015) was an American graph theorist specializing in topological graph theory, who served for many years as a professor of mathematics and statistics at the University of Vermont.
| International | |
|---|---|
| National | |
| Academics | |
| Other | |
