Oriented, 2-edge-colored, and 2-vertex-colored homomorphisms
نویسندگان
چکیده
منابع مشابه
Oriented, 2-edge-colored, and 2-vertex-colored homomorphisms
We show that the 2-edge-colored chromatic number of a class of simple graphs is bounded if and only if the acyclic chromatic number is bounded for this class. Recently, the CSP dichotomy conjecture has been reduced to the case of 2-edge-colored homomorphism and to the case of 2-vertex-colored homomorphism. Both reductions are rather long and follow the reduction to the case of oriented homomorp...
متن کاملHomomorphisms of 2-edge-colored graphs
In this paper, we study homomorphisms of 2-edge-colored graphs, that is graphs with edges colored with two colors. We consider various graph classes (outerplanar graphs, partial 2-trees, partial 3-trees, planar graphs) and the problem is to find, for each class, the smallest number of vertices of a 2-edge-colored graph H such that each graph of the considered class admits a homomorphism to H.
متن کاملHomomorphisms of 2-Edge-Colored Triangle-Free Planar Graphs
In this article, we introduce and study the properties of some target graphs for 2-edge-colored homomorphism. Using these properties, we obtain in particular that the 2-edge-colored chromatic number of the class of triangle-free planar graphs is at most 50. We also show that it is at least 12. C © 2016 Wiley Periodicals, Inc. J. Graph Theory 00: 1–20, 2016
متن کاملColored Homomorphisms of Colored Mixed Graphs
The homomorphisms of oriented or undirected graphs, the oriented chromatic number, the relationship between acyclic coloring number and oriented chromatic number, have been recently studied. Improving and combining earlier techniques of N. Alon and T. H. Marshall (1998, J. Algebraic Combin. 8, 5 13) and A. Raspaud and E. Sopena (1994, Inform. Process. Lett. 51, 171 174) we prove here a general ...
متن کاملMonochromatic subgraphs of 2-edge-colored graphs
Lehel conjectured that for all n, any 2-edge-coloring of Kn admits a partition of the vertex set into a red cycle and a blue cycle. This conjecture led to a significant amount of work on related questions and was eventually proven for all n by Bessy and Thomassé. Balogh, Barát, Gerbner, Gyárfás, and Sárközy conjectured a stronger statement for large n: that if δ(G) > 3n/4, then any 2-edge-color...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Information Processing Letters
سال: 2017
ISSN: 0020-0190
DOI: 10.1016/j.ipl.2017.02.009