Title
Distinguishability of Infinite Groups and Graphs.
Abstract
The distinguishing number of a group G acting faithfully on a set V is the least number of colors needed to color the elements of V so that no non-identity element of the group preserves the coloring. The distinguishing number of a graph is the distinguishing number of its automorphism group acting on its vertex set. A connected graph Gamma is said to have connectivity 1 if there exists a vertex alpha is an element of V Gamma such that Gamma \ {alpha} is not connected. For alpha is an element of V, an orbit of the point stabilizer G(alpha) is called a suborbit of G. We prove that every nonnull, primitive graph with infinite diameter and countably many vertices has distinguishing number 2. Consequently, any nonnull, infinite, primitive, locally finite graph is 2-distinguishable; so, too, is any infinite primitive permutation group with finite suborbits. We also show that all denumerable vertex-transitive graphs of connectivity 1 and all Cartesian products of connected denumerable graphs of infinite diameter have distinguishing number 2. All of our results follow directly from a versatile lemma which we call The Distinct Spheres Lemma
Year
Venue
Keywords
2012
ELECTRONIC JOURNAL OF COMBINATORICS
distinguishing number,primitive permutation group,primitive graph,Distinct Spheres Condition,infinite motion,Cartesian product of graphs
Field
DocType
Volume
Graph automorphism,Discrete mathematics,Combinatorics,Graph toughness,Infinite group,Line graph,Cartesian product of graphs,Cycle graph,Symmetric graph,Universal graph,Mathematics
Journal
19.0
Issue
ISSN
Citations 
2.0
1077-8926
8
PageRank 
References 
Authors
1.21
5
3
Name
Order
Citations
PageRank
Simon M. Smith181.21
Thomas W. Tucker2191130.07
Mark E. Watkins310932.53