CWI Lexures: Discrete Mathematics and Optimization (2013)

We cordially invite you to attend the 'CWI Lexures on Discrete Mathematics and Optimization' on 25 April 2013 at the Centrum Wiskunde & Informatica in Amsterdam. This year's CWI Lectures are organized in honour of Lex Schrijver, on the occasion of his retirement.
  • CWI Lexures: Discrete Mathematics and Optimization (2013)
  • 2013-04-25T08:30:00+02:00
  • 2013-04-25T17:00:00+02:00
  • We cordially invite you to attend the 'CWI Lexures on Discrete Mathematics and Optimization' on 25 April 2013 at the Centrum Wiskunde & Informatica in Amsterdam. This year's CWI Lectures are organized in honour of Lex Schrijver, on the occasion of his retirement.
  • What Everybody Lectures
  • When 25-04-2013 from 08:30 to 17:00 (Europe/Amsterdam / UTC200)
  • Where CWI, Turing room
  • Add event to calendar iCal

We cordially invite you to attend the 'CWI Lexures on Discrete Mathematics and Optimization' on 25 April 2013 at the Centrum Wiskunde & Informatica in Amsterdam. This year's CWI Lectures are organized in honour of Lex Schrijver, on the occasion of his retirement. 


Lex Schrijver is a world-renowned authority on discrete mathematics and optimization. In 2005 Lex Schrijver was awarded the prestigious NWO Spinoza Prize, the highest scientific award in the Netherlands. He is best known to the general public for his work on the optimization of the Dutch railway timetables.

The CWI Lectures 2013 in mathematics and computer science are organized by CWI's Networks & Optimization group.


Invited speakers

The program features five speakers who are related to the research and career of Lex Schrijver, including:

  • László Lovász (Eötvös Lórand University, Hungary)
  • Martin Grötschel (Konrad-Zuse-Zentrum für Informationstechnik Berlin, Germany)
  • Willem Haemers (Tilburg University, the Netherlands)
  • Dion Gijswijt (CWI / Delft University of Technology, the Netherlands)
  • Leo Kroon (Erasmus University Rotterdam / Netherlands Railways/NS)

Program (tentative)

10:30 - 11:00    Welcome with coffee & tea
11:00 - 11:05    Opening

11:05 - 11:50    László Lovász
11:50 - 12:35    Martin Grötschel

12:35 - 13:40    Lunch

13:40 - 14:10    Willem Haemers
14:10 - 14:40    Dion Gijswijt
14:40 - 15:10    Leo Kroon

15:10 - 15:30    Coffee & tea

15:30 - 16:30    Speeches

15:30 - 15-40    Jan Karel Lenstra
15:40 - 15:50    Krzysztof Apt
15:50 - 16:00    Leen Stougie
16:00 - 16:10    Jan Wiegerinck
16:10 - 16:15    Jos Baeten
16:15 - 16:20    Rob van der Mei
16:20 - 16:30    Lex Schrijver

16:30 - 19:00    Reception and walking dinner


László Lovász:

Graph algebras and extremal graph theory

Algebras generated by partially labeled graphs have been introduced by  Freedman, Lovasz and Schrijver, as a tool for the characterization of homomorphism functions. In this paper, we survey some applications of them in extremal graph theory: characterizing linear inequalities between subgraph densities, and a potential application to characterize the possible structures of extremal graphs. 

Willem  Haemers (see enclosed pdf)

Dion Gijswijt:

Independent sets in symmetric graphs

In 2006, Lex Schrijver published a new method for obtaining bounds for the size of binary codes. The method combined at least two beautiful ideas: approximating a discrete problem by increasingly tight semidefinite relaxations, and a way to exploit the underlying symmetry group to (dramatically) reduce the problem size.

This method can be adapted to a wide range of (symmetric) optimization problems and its success has spurred much research in the last 7 years.

Guided by a recreational conjecture on tiling cubes, we expose some of the mathematical ideas. 

Leo Kroon:

Challenges after CADANS

Lex Schrijver's first contribution to railway optimization was the development of the CADANS model for generating periodic railway timetables, mainly represented by departure and arrival times of trains.  The development of CADANS was important in its own, but it was even more important since it showed for the first time that railway planning problems can not only be solved by human planners based on their experience and craftsmanship, but also by computers. The development of CADANS was the starting point of the development of other railway optimization models for station routing, rolling stock circulation, and crew scheduling. These models are used nowadays on a daily basis in the planning processes of Netherlands Railways. The current development focuses on the application of these optimization models for disruption management in case of large disturbances of the railway system. Here several challenges are still to be tackled, such as short computation times, uncertainty, and a highly dynamic environment. These challenges will be illustrated in this presentation.


Registration has been closed as per 24 April.


For further informations and questions concerning the CWI Lexures, please contact Susanne van Dam


Here is an interesting video of the Simons foundation featuring László Lovász interviewed by Avi Wigderson.

Guest list

Aart Blokhuis
Adri Steenbeek
Aida Abiad
Aleksander Brancewicz
Anargyros Katsampekis  
Angelique Schilder
Annette Kik  
Antonios Varvitsiotis  
Ay Ong  
Bart de Keijzer  
Bert van Es
Bodo Manthey  
Caroline Jagtenberg  
Christian Schaffner  
Christine Staiger  
Christos Pelekis
Coby Geijsel  
Coby van Vonderen  
Cor Baaijen
Cor Hurkens
David de Laat  
Dick den Hertog  
Dion Gijswijt  
Ed Veling
Edwin de Boer
Edwin van Dam
Ellis Binnenmarsch      
Erik van Doorn
Evalien IJsendijk  
Evan DeCorte  
Evelien Wallet   
Femke van Raamsdonk  
Fernando de Melo  
Frank de Boer  
Frank den Hollander     
Frank Kuiper
Frank van der Duyn Schouten 
G.Y. Nieuwland  
Gerard Kindervater  
Giannicola Scarpa
Guido Schaefer 
Gunnar Klau  
Guus Regts
Guus schippers
Han Hoogeveen  
Hans Schumacher  
Hans Vonk
Harry Buhrman  
Hendrik Lenstra  
Henk Nieland  
Herbert hamers  
Herman te Riele  
Hette Weijma
Ieke Moerdijk
Ignacio Cascudo
Inez Fikkers
Iris Grötschel 
Irving van Heuven van Staereling
Jaap Korevaar
Jacob Engwerda  
Jan Draisma
Jan Karel Lenstra
Jan Kok  
Jan Rutten  
Jan Schipper
Jan van Leeuwen
Jan van Mill
Jan Wiegerinck  
Jason Frank  
Jetske Schrijver
Joek van Montfort
Joost Batenburg
Jose Koster
Juan Vera  
Judith Keijsper  
Juliette Schrijver  
Kacha Dzhaparidze  
Kamiel Cornelissen  
Karin van Gemert
Katalin Vesztergombi 
Kees de Vreugd  
Kees Oosterlee  
Kees van den Hoeven  
Ko Anthonisse  
Krzysztof R. Apt  
Laslo Lovasz  
Leen Stougie  
Leo Kroon  
Leo van Iersel  
Lex Schrijver  
Lex Zandee  
Lieke Schultze  
Lieske Schrijver
Lotte de Jonker
Luis Ortiz Gracia 
Lynda Hardman  
Maarten Dijkema  
Marc Uetz  
Marcus Klaas  
Margreet Nool  
Marie-Colette van Lieshout  
Mariska Heemskerk
Marja Braxhoofden  
Marja Hegt  
Marlin van der Heijden  
Martin Grötschel  
Martyn Mulder  
Matthijs Coster  
Matthijs Schukking
Mees de Vries
Michael Guravage  
Michel Mandjes  
Miriam Gravemaker  
Monique Laurent  
Murray Patterson
Nada Mitrovic  
Nebojla Gvozdenovic
Nella Schrijver 
Onno Boxma
Paul Klint  
Paul Vitanyi  
Peter de Paepe
Peter Grünwald  
Peter Hildering
Peter Schrijver
Peter van Emde Boas
Petra de Bont
Piet Beertema  
Piet Hemker  
Pieter van den Berg
Rob Bisseling  
Rob van den Berg
Rob van der Mei  
Robbert de Haan 
Robbert Fokkink
Robert van Liere  
Robert W. van der Waall
Roel Niessen  
Roelof Helmers
Ronald de Wolf  
Ross Kang
Ruben Brokkelkamp
Rudi Pendavingh
Rutger Kerkkamp
Sander Bohte
Serge Fehr
Simone van der Wolff
Sindo Nunez Queija
Stefan Manegold
Sumit Sourabh
Sunil Simon
Susanne van Dam
Takanori Hida
Teresa Piovesan
Teun Janssen
Thije van Barneveld
Thijs van Ommen
Tim Oosterwijk
Tobias Baanders
Tobias Muller
Ulle Endriss
Vadim Zaytsev
Wieb Bosma
Willem Haemers
Willem Hundsdorfer
Wilmy van Ojik
Wouter Koolen-Wijkstra
Wouter Mettrop
Yagiz Kargin
Yuri Matteman
Zhao Sun