## Abstract In this paper we obtain chromatic polynomials of connected 3‐ and 4‐chromatic planar graphs that are maximal for positive integer‐valued arguments. We also characterize the class of connected 3‐chromatic graphs having the maximum number of __p__‐colorings for __p__ ≥ 3, thus extending a
Maximum chromatic polynomials of 2-connected graphs
✍ Scribed by Ioan Tomescu
- Publisher
- John Wiley and Sons
- Year
- 1994
- Tongue
- English
- Weight
- 345 KB
- Volume
- 18
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
In this paper we obtain chromatic polynomials P(G; λ) of 2‐connected graphs of order n that are maximum for positive integer‐valued arguments λ ≧ 3. The extremal graphs are cycles C~n~ and these graphs are unique for every λ ≧ 3 and n ≠ 5.
We also determine max{P(G; λ): G is 2‐connected of order n and G ≠ C~n~} and all extremal graphs relative to this property, with some consequences on the maximum number of 3‐colorings in the class of 2‐connected graphs of order n having ~X~(G) = 2 and ~X~(G) = 3, respectively. For every n ≧ 5 and λ ≧ 4, the first three maximum chromatic polynomials of 2‐connected graphs are determined.
📜 SIMILAR VOLUMES
## Abstract In the set of graphs of order __n__ and chromatic number __k__ the following partial order relation is defined. One says that a graph __G__ is less than a graph __H__ if __c__~__i__~(__G__) ≤ __c__~__i__~(__H__) holds for every __i__, __k__ ≤ __i__ ≤ __n__ and at least one inequality is
## Abstract A graph __G__ is critically 2‐connected if __G__ is 2‐connected but, for any point __p__ of __G, G — p__ is not 2‐connected. Critically 2‐connected graphs on __n__ points that have the maximum number of lines are characterized and shown to be unique for __n__ ⩾ 3, __n__ ≠ 11.
## Abstract This paper proves that if __G__ is a graph (parallel edges allowed) of maximum degree 3, then χ′~__c__~(__G__) ≤ 11/3 provided that __G__ does not contain __H__~1~ or __H__~2~ as a subgraph, where __H__~1~ and __H__~2~ are obtained by subdividing one edge of __K__ (the graph with three
Frucht and Giudici classified all graphs having quadratic a-polynomials. Here w e classify all chromatically unique graphs having quadratic (Tpolynomials.
## Abstract In this article we prove that the total chromatic number of a planar graph with maximum degree 10 is 11. © 2006 Wiley Periodicals, Inc. J Graph Theory 54: 91–102, 2007