4 papers
Winding number and circular coloring
Reza Naserasr, Cyril Pujol, Lujia Wang
In 1996, Youngs proved a surprising theorem that quadrangulations of the projective plane could never have chromatic number exactly 3. This sparked a lot of interest, and the resul…
Extension of the Gyárfás-Sumner conjecture to signed graphs
Guillaume Aubian, Allen Ibiapina, Luis Kuffner +4
The balanced chromatic number of a signed graph G is the minimum number of balanced sets that cover all vertices of G. Studying structural conditions which imply bounds on the bala…
Fractional balanced chromatic number and arboricity of planar (signed) graphs
Reza Naserasr, Lan Anh Pham, Cyril Pujol +1
A fractional coloring of a signed graph is an assignment of nonnegative weights to the balanced sets (sets which do not induce a negative cycle) such that each vertex has…
On core of categorical product of (di)graphs
Reza Naserasr, Cyril Pujol
The core of a graph is the smallest graph (in terms of number of vertices) to which it is homomorphically equivalent. The question of the possible order of the core of the tensor p…