Workshop 2022

An international meeting by invitation only to be held at

La Villa Clythia CAES du CNRS, Fréjus.

Research scopes are coloring problems closely related to the main projects of HOSIGRA.

Date: 19-26 June, 2022

The list of participants

Research topics of the meeting


Breakfast 7:30--9:00, Coffee-Break 11:15, Lunch 12:39, Coffee-Break 16:?? Dinner 19:30

Monday June 20th

9:00-11:15: Introduction of participants followed by introduction of notion (Reza Naserasr), and then sharing open problems (Ben Moore, Mária Maceková, Zhouninxin Wang).

11:30-12:30: Penny Haxell, Graphs with high chromatic number.

Afternoon, work in groups. Denis Cornaz presented a proof of: in an (K_4,-)-minor free signed graph max number of edge-disjoint cycles is equal to frustration index.

Tuesday June 21


Eckhard Steffen, Frustration index

Matej Stehlík, Odd girth of 4-chromatic graphs

Tomáš Kaiser, Edge-critical subgraphs of Schrjiver graphs

Rest of the day: working in small groups.

Wednesday June 22


Bojan Mohar, Z_3-flow-critical graphs

Zhouningxin Wang, circular flow in mono-directed signed graphs

After 11:30

Work on projects

Thursday June 23


Progress report by a representative from each project: Sagnik Sen, Alexandre Pinlou, Frantisek Kardos, Daniel Quiroz, Chiara Cappello, Tomáš Kaiser, Bojan Mohar

After 11:30

Continue work on projects

Friday June 24

A short progress discussion at 9:00 follow by focus on projects,

Saturday June 25

Summarizing what was done on each project and making plans to continue the discussions.