Title
Growing Without Cloning.
Abstract
A graph G is claw-free if no induced subgraph of it is isomorphic to the complete bipartite graph K-1,K-3, and it is prime if vertical bar V (G)vertical bar >= 4 and there is no X subset of V (G) with 1 < vertical bar X vertical bar < vertical bar V (G)vertical bar such that every vertex of V(G) \ X with a neighbor in X is adjacent to every vertex of X. In particular, if G is prime, then both G and G(c) are connected. This paper has two main results. The first one is that if G is a prime graph that is not a member of a particular family of exceptions, and H is a prime induced subgraph of G, then ( up to isomorphism) G can be grown from H, adding one vertex at a time, in such a way that all the graphs constructed along the way are prime induced subgraphs of G. A simplicial clique in G is a nonempty clique K such that for every k is an element of K the set of neighbors of k in V (G) \ K is a clique. Our second result is that a prime claw-free graph G has at most vertical bar V(G)vertical bar + 1 simplicial cliques, and we give an algorithm to find them all with running time O(vertical bar V (G)vertical bar(4)). In particular, this answers a question of Prasad Tetali [private communication] who asked if there is an efficient algorithm to test if a claw-free graph has a simplicial clique. Finally, we apply our results to claw-free graphs that are not prime. Such a graph may have exponentially many simplicial cliques, so we cannot list them all in polynomial time, but we can in a sense describe them.
Year
DOI
Venue
2012
10.1137/100817255
SIAM JOURNAL ON DISCRETE MATHEMATICS
Keywords
Field
DocType
prime graphs,induced subgraphs,splitter theorem,claw-free graphs,simplicial clique
Prime (order theory),Complete bipartite graph,Discrete mathematics,Graph,Combinatorics,Vertex (geometry),Clique,Induced subgraph,Isomorphism,Mathematics
Journal
Volume
Issue
ISSN
26
2
0895-4801
Citations 
PageRank 
References 
0
0.34
5
Authors
2
Name
Order
Citations
PageRank
Maria Chudnovsky139046.13
Paul D. Seymour22786314.49