Willem Haemers

Major fields

Discrete mathematics, combinatorics, algebraic graph theory, finite geometry, design theory and coding theory.

Publications

Research portal Tilburg University; ResearchGate; arXiv.

Spectra of Graphs, with Andries E. Brouwer, textbook, Springer Universitext, 2012.

The Beauty of Discrete Mathematics, Asset Magazine 26 (2011) 16-19.

Discreet en Mooi, Inaugurele rede (inaugural speech in Dutch), September 4, 2009).

Toughness conjecture, A conjecture on the toughness of a graph; a lower bound in terms of the Laplacian spectrum.

Eigenvalue techniques in design and graph theory, Ph.D. thesis (1979).

An inequality for near hexagons, with Rudi Mathon, unpublished manuscript, 1979.

Editorial

Editor (former editor-in-chief) of The Electronic Journal of Combinatorics.

Former editor of Innovations in Incidence Geometry.

Former member of the editorial board of Designs, Codes and Cryptography.

Member of the advisory board of Publications de l'Institut Mathématique (Serbia).

Conferences and workshops

Autumn Workshop on Algebraic Combinatorics. November 8-9, 2025, Shijiazhuang.

Other things and links

Reader with Addendum for a series of lectures on "Matrix techniques for strongly regular graphs and related geometries", given in Ghent (April 2000).

Videos of an advanced course on eigenvalue techniques in graph theory given in Barcelona (June 2011).

1. Interlacing; the appetizer. 2. More interlacing for the adjacency matrix. 3. Perfect matchings. 4. Regularity and spectral characterizations.

Aida Abiad, Andries E. Brouwer, Edwin van Dam, Ted Spence.

UvTmail, Ziggomail.

Paintings by Katrien Haemers.

Address

Department of Econometrics and Operations Research,

Tilburg University,

P.O. Box 90153,

5000 LE Tilburg,

The Netherlands

Tel. +31-134662777

Fax +31-134663280

E-mail haemers at uvt dot nl