On Coloring Catalan Number Distance Graphs and Interference Graphs

• Main Authors: Venkataraman Yegnanarayanan, Gayathri Narayana Yegnanarayanan, Marius M. Balas
• Format: Article
• Language: English
• Published: MDPI AG 2018-10-01
• Series: Symmetry
• Subjects: chromatic number; distance graphs; interference graphs; Catalan numbers; Hankel transforms; chromatic threshold
• Online Access: http://www.mdpi.com/2073-8994/10/10/468

A vertex coloring of a graph G is a mapping that allots colors to the vertices of G. Such a coloring is said to be a proper vertex coloring if two vertices joined by an edge receive different colors. The chromatic number χ ( G ) is the least number of colors used in a proper vertex coloring. In this paper, we compute the χ of certain distance graphs whose distance set elements are (a) a finite set of Catalan numbers, (b) a finite set of generalized Catalan numbers, (c) a finite set of Hankel transform of a transformed sequence of Catalan numbers. Then while discussing the importance of minimizing interference in wireless networks, we probe how a vertex coloring problem is related to minimizing vertex collisions and signal clashes of the associated interference graph. Then when investigating the χ of certain G ( V , D ) and graphs with interference, we also compute certain lower and upper bound for χ of any given simple graph in terms of the average degree and Laplacian operator. Besides obtaining some interesting results we also raised some open problems.