Spanning k-Ended Tree in 2-Connected Graph

Win proved a very famous conclusion that states the graph G with connectivity κ(G), independence number α(G) and α(G)≤κ(G)+k−1(k≥2) contains a spanning k-ended tree. This means that there exists a spanning tree with at most k leaves. In this paper, we strengthen the Win theorem to the following: Let G be a simple 2-connected graph such that |V(G)|≥2κ(G)+k, α(G)≤κ(G)+k(k≥2) and the number of maximum independent sets of cardinality κ+k is at most n−2κ−k+1. Then, either G contains a spanning k-ended tree or a subgraph of Kκ∨((k+κ−1)K1∪Kn−2κ−k+1).