On the chromatic number of a subgraph of the Kneser graph

Autor: Bart Sevenster, Bart Litjens, Lluís Vena, Sven Polak
Přispěvatelé: Algebra, Geometry & Mathematical Physics (KDV, FNWI)
Jazyk: angličtina
Rok vydání: 2018
Předmět:
Zdroj: Electronic Notes in Discrete Mathematics, 68, 227-232. Elsevier
Electronic Notes in Discrete Mathematics, 68, 227-232
ISSN: 1571-0653
DOI: 10.1016/j.endm.2018.06.039
Popis: Let n and k be positive integers with n ≥ 2 k . Consider a circle C with n points 1 , … , n in clockwise order. The interlacing graph IG n , k is the graph with vertices corresponding to k-subsets of [n] that do not contain two adjacent points on C, and edges between k-subsets P and Q if they interlace: after removing the points in P from C, the points in Q are in different connected components. In this paper we prove that the circular chromatic number of IG n , k is equal to n / k , hence the chromatic number is ⌈ n / k ⌉ , and that its independence number is ( n − k − 1 k − 1 ) .
Databáze: OpenAIRE