Abstract
Let \(G\) be a connected graph of order \(n\) . For any integer \(k\geq2\) , a spanning \(k\) -tree of \(G\) is a spanning tree in which every vertex has degree at most \(k\) . In this paper, we provide a tight \(A_{\alpha}\) -spectral condition to guarantee the existence of a spanning \(k\) -tree in \(G\) with extremal graphs being characterized. Moreover, we also present tight \(A_{\alpha}\) -spectral conditions for \(G\) admitting a spanning \(k\) -ended-tree (i.e., a spanning tree with at most \(k\) leaves) and determine the extremal graphs.