I am a mathematician living and working in Sittard, the Netherlands.
Since 1999,
Jim Geelen
(University of Waterloo),
Geoff Whittle
(Victoria University of Wellington), and
I work on extending Robertson and Seymour’s Graph Minor Theory to
matroids representable over finite fields and on
Rota’s Conjucture
from 1970 that
such representability can be characterized by finitely many excluded minors.
This joint Matroid Minor Project turned out to require tremendous effort.
It took us 12 year to complete our Matroid Minor Structure Theorem and
then another year or so to also prove Rota’s Conjecture;
see
Solving Rota's conjecture in Notices AMS, August 2014.
We are still involved in writing down the full details of all this work.
Part of this I also do together with
Tony Huynh (Monash University).
I talked about this work and what it means doing it in an interview (in dutch) in Observant in 2013,
and so did
Jim in The Waterloo Region Record and Geoff on Radio New Zealand.
Biography.
I obtained my PhD from Tilburg University in 1988,
where I was an assistant professor from 1984 till I joined
Centrum Wiskunde & Informatica (CWI) in Amsterdam as a senior researcher in 1989.
I had already started my PhD research in 1982,
when I switched from being a high school teacher in Maastricht to become a research
assistant of NWO
(first at the University of Amsterdam and then at Tilburg University).
I went to high school (HBSB) in Sittard from 1967 till 1972 and
did my masters studies at Eindhoven University of Technology from 1972 till 1981.
While at CWI, I also was parttime full professor at
Eindhoven University of Technology (19992009) and Maastricht University (20102014).
From 2008 till 2012, I held an (honorary) position as adjoint professor in
the Department of Combinatorics and Optimization at the University of Waterloo.
From 1999 till 2007, I served on the editorial boards of Mathematical Programming, Series A
and SIAM Journal on Discrete Mathematics.
From 1997 till 2009, I held several management positions at CWI;
from 2005 till 2009, I was member of the CWI Management Team.
Early 2021, I left CWI.
I am a 2003
Fulkerson Prize recipient
and gave an
invited lecture at the 2006 International Congress of Mathematicians in Madrid.

