This was a second year of a project for developing signed graph homomorphisms.

The main meeting was again held October 19-25, 2013, at la la Gabertie, Thezac.

Co-organizers: Laurent Beadou, Alexandre Pinlou and Eric Sopena.


Vesna Andova, Larent Beaudou, Julien Bensmail, Richard Brewster, Chris Duffy, David Forge, Florent Foucaud, Gena Hann, Pavol Hell, Frantisek Kardos, Sylvain Legay, Nazanin Movarraei, Reza Naserasr, Pascal Ochem, Alexandre Pinlou, Andre Raspaud, Sagnik Sen, Riste Skrekovski, Eric Sopena, Qiang Sun,

Accompanying: Dominique Sotteau, Ipsita

Cheff: Tom Hrdina,


First day Eric presented most of the progress on the new concept of signed graph homomorphisms. Following Eric's talk, I presented a list of problems to continue working on.

For the rest of the week, just like the previous year, each morning, after the breakfast, we had a meeting to discuss the new ideas from the previous day(s). Then we split into small groups to work on our favorite subject.

A lecture on the subject of list homomorphisms was given by Pavol Hell.

Title of research problem considered:

  1. Signed chromatic number of signed planar graphs
  2. Zaslavski chromatic number of signed planar graphs,
  3. Analogue of Zeager-Zhang conjecture for signed bipartite graphs
  4. Complexity of (G, \Sigma)-coloring
  5. Extensions to reflexive graphs,
  6. Extensions of Hadwiger's conjecture

As of December 2013 some papers based on results from this meeting are to be written.

Group photos of the meeting: