The odd chromatic number of a graph G is the minimum k such that G admits a proper coloring such that in the neighborhood of every (non-isolated) vertex, some color appears an odd number of times. I will give some overview, results, and problems on the behavior of this parameter in comparison to the usual chromatic number. This is based on different joint works with James Davies, Meike Hatzel, Andrea Jiménez, Carla Negri Lintzmayer, Martín Matamala, Rose McCarty, Juan Pablo Peña, Daniel A. Quiroz, Maycon Sambinelli, Torsten Ueckerdt, Yoshiko Wakabayashi, Weiqiang Yu, and José Zamora.

Kolja Knauer is a professor at the University of Barcelona and specializes in graph theory and its connections to algebra, geometry, and matroid theory. He did his PhD in Berlin and has coauthored 3 books and about 70 research articles.