Zdeněk Dvořák (born April 26, 1981) is a Czech mathematician specializing in
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 conne ...
.
Dvořák was born in
Nové Město na Moravě.
He competed on the Czech national team in the 1999
International Mathematical Olympiad
The International Mathematical Olympiad (IMO) is a mathematical olympiad for pre-university students, and is the oldest of the International Science Olympiads. The first IMO was held in Romania in 1959. It has since been held annually, except i ...
, and in the same year in the
International Olympiad in Informatics, where he won a gold medal. He earned his Ph.D. in 2007 from
Charles University in Prague
Charles University ( cs, Univerzita Karlova, UK; la, Universitas Carolina; german: Karls-Universität), also known as Charles University in Prague or historically as the University of Prague ( la, Universitas Pragensis, links=no), is the oldest an ...
, under the supervision of
Jaroslav Nešetřil. He remained as a research fellow at Charles University until 2010, and then did postdoctoral studies at the
Georgia Institute of Technology
The Georgia Institute of Technology, commonly referred to as Georgia Tech or, in the state of Georgia, as Tech or The Institute, is a public research university and institute of technology in Atlanta, Georgia. Established in 1885, it is part of ...
and
Simon Fraser University. He then returned to the Computer Science Institute (IUUK) of Charles University, obtained his
habilitation
Habilitation is the highest university degree, or the procedure by which it is achieved, in many European countries. The candidate fulfills a university's set criteria of excellence in research, teaching and further education, usually including a ...
in 2012, and has been a full professor there since 2022.
[.]
He was one of three winners of the 2015
European Prize in Combinatorics, "for his fundamental contributions to graph theory, in particular for his work on structural aspects of graph theory, including solutions to Havel's 1969 problem and the Heckman–Thomas 14/5 problem on fractional colourings of cubic triangle-free graphs. This refers to two different results of Dvořák:
*Havel's conjecture is a strengthening of
Grötzsch's theorem. It states that there exists a constant ''d'' such that, if a
planar graph
In graph theory, a planar graph is a graph that can be embedded in the plane, i.e., it can be drawn on the plane in such a way that its edges intersect only at their endpoints. In other words, it can be drawn in such a way that no edges cross ...
has no two triangles within distance ''d'' of each other, then it can be
colored with three colors. A proof of this conjecture of Havel was announced by Dvořák and his co-authors in 2009.
*C. C. Heckman and
Robin Thomas conjectured in 2001 that
triangle-free graphs of maximum degree three have
fractional chromatic number
Fractional coloring is a topic in a young branch of graph theory known as fractional graph theory. It is a generalization of ordinary graph coloring. In a traditional graph coloring, each vertex in a graph is assigned some color, and adjacent ver ...
at most 14/5. A proof was announced by Dvořák and his co-authors in 2013 and published by them in 2014.
[.]
References
External links
Home page
{{DEFAULTSORT:Dvorak, Zdenek
1981 births
Living people
Czech mathematicians
Graph theorists
Charles University alumni
Academic staff of Charles University