Professor Patric R. J. Östergård's home page
If you want to contact me,
see
this page.
The University of Pécs conferred the degree of
"Doctor et Professor Honoris Causa" on me
at a ceremony held in Pécs, Hungary, on 7 November 2013.
Research interests
I am interested in a wide variety of problems in mathematics,
telecommunications, and computer science. In particular, I am interested in
using computers to find and classify mathematical objects.
My research themes can roughly be divided into the following
groups:

Mathematical objects
 Codes (covering codes, errorcorrecting codes, etc.)
 Combinatorial designs
 Other structures that can be viewed as packings or coverings

Combinatorial algorithms
 Stochastic optimization methods, local search algorithms (tabu search)
 Exact algorithms for (NP)hard problems
 Graph algorithms for clique and coloring problems
 Algorithms for isomorphism testing; classification algorithms

Information theory, in general

Discrete mathematics, in general
Recent and old news
The monograph
Classification
Algorithms for Codes and Designs,
coauthored with Petteri Kaski,
is to be found in a bookshop near you.
Some sporadic results:
This is an old one:
There are 11,084,874,829 Steiner triple systems of order 19;
see a
paper by Petteri Kaski and myself.
There are 5983 perfect binary oneerrorcorrecting codes of
length 15; see the
paper.
Together with
Sampo Niskanen, we have developed Cliquer, routines
for clique searching. The first public release (1.0) was
made in late 2002; the current release (1.21) can be found
here.
I am a recipient of the 1996 Kirkman Medal, awarded by
The Institute of Combinatorics and its Applications.
I am coEditorinChief of the
Journal of Combinatorial Designs.
My research is financed in part by the
Academy of Finland.
I spent the year 1996 at the
Department of Mathematics and Computing Science,
Eindhoven University of Technology, the Netherlands. I spent
the spring 2010 at the University of Bayreuth, Germany.
Publications
Here are (in pdf) some recent papers that have been
accepted for publication. I also maintain a list of
all my publications.
Total domination of grid graphs,
S. Crevals and P. R. J. Östergård,
Journal of Combinatorial Mathematics and Combinatorial Computing,
to appear.
New lower bounds for the Shannon capacity of odd cycles,
K. A. Mathew and P. R. J. Östergård,
Designs, Codes and Cryptography, to appear.
On the domination number of 2dimensional torus graphs,
S. Crevals and P. R. J. Östergård,
Utilitas Mathematica, to appear.
New lower bounds for binary constantdimension subspace codes,
M. Braun, P. R. J. Östergård, and A. Wassermann,
Experimental Mathematics, to appear.
Other interests
A marathon race takes only a
little bit more than 2 hours for the elite. That is far from
being a real endurance sport. You have to increase the
running distance beyond 100k to find out who really has
endurance. I have myself taken part in marathons in different
sports. I maintain a list of
all marathons that I have completed. For other sports
than running, I have listed events that are at least 50k.
Latest update: March 31, 2017.