The Turán number of star forests.

Abstract The Turán number of a graph H , denoted by ex (n, H), is the maximum number of edges in any graph on n vertices containing no H as a subgraph. Let S ℓ denote the star on ℓ + 1 vertices and let k · S ℓ denote disjoint union of k copies of S ℓ. In this paper, for appropriately large n , we determine the Turán numbers for k · S ℓ and F , where F is a forest with components each of order 4, which improve the results of Lidický et al. (2013). [ABSTRACT FROM AUTHOR]