Title
Counting copies of a fixed subgraph in $F$-free graphs
Abstract
Fix graphs F and H and let ex(n,H,F) denote the maximum possible number of copies of the graph H in an n-vertex F-free graph. The systematic study of this function was initiated by Alon and Shikhelman [J. Comb. Theory, B. 121 (2016)]. In this paper, we give new general bounds concerning this generalized Turán function. We also determine ex(n,Pk,K2,t) (where Pk is a path on k vertices) and ex(n,Ck,K2,t) asymptotically for every k and t. For example, it is shown that for t≥2 and k≥5 we have ex(n,Ck,K2,t)=12k+o(1)(t−1)k∕2nk∕2. We also characterize the graphs F that cause the function ex(n,Ck,F) to be linear in n. In the final section we discuss a connection between the function ex(n,H,F) and Berge hypergraph problems.
Year
DOI
Venue
2019
10.1016/j.ejc.2019.103001
European Journal of Combinatorics
Field
DocType
Volume
Discrete mathematics,Graph,Combinatorics,Vertex (geometry),Hypergraph,Mathematics
Journal
82
ISSN
Citations 
PageRank 
0195-6698
1
0.36
References 
Authors
11
2
Name
Order
Citations
PageRank
Dániel Gerbner14621.61
Cory Palmer24410.33