Title
Inapproximability results and bounds for the Helly and Radon numbers of a graph.
Abstract
Let C be a convexity on a set X and denote the convex hull of S⊆X in C by H(S). The Helly number (Radon number) of C is the minimum integer k such that, for every S⊆X with at least k+1 elements, it holds ⋂v∈SH(S∖{v})≠∅ (there is a bipartition of S into sets S1 and S2 with H(S1)∩H(S2)≠∅). In this work, we show that there is no approximation algorithm for the Helly or the Radon number of a graph G of order n in the geodetic convexity to within a factor n1−ε for any ε>0, unless P = NP, even if G is bipartite. Furthermore, we present upper bounds for both parameters in the geodetic convexity of bipartite graphs and characterize the families of graphs achieving the bound for the Helly number.
Year
DOI
Venue
2017
10.1016/j.dam.2017.07.032
Discrete Applied Mathematics
Keywords
Field
DocType
Bipartite graphs,Geodetic convexity,Helly number,Inapproximability,Radon number,Upper bound
Integer,Approximation algorithm,Discrete mathematics,Geodetic datum,Combinatorics,Convexity,Helly's theorem,Radon,Bipartite graph,Convex hull,Mathematics
Journal
Volume
Issue
ISSN
232
C
0166-218X
Citations 
PageRank 
References 
0
0.34
4
Authors
2
Name
Order
Citations
PageRank
Mitre Dourado19018.43
Aline R. da Silva200.34