Spanning trees of $K_{1,4}$-free graphs whose reducible stems have few leaves

Pham Hoang Ha, Le Dinh Nam, Ngoc Diep Pham

Let $T$ be a tree, a vertex of degree one is a \emph{leaf} of $T$ and a vertex of degree at least three is a \emph{branch vertex} of $T$. The {\it reducible stem } of $T$ is the sm…