“…E-mail address: amarin@um.es to the structure of the tree. Some problems within this family are the Minimum Leaf STP (Cerrone, Cerulli, & Raiconi, 2014;Salamon & Wiener, 2008), the Full Degree STP (also called Degree Preserving STP) (Bhatia, Khuller, Pless, & Sussmann, 1999;Gendron, Lucena, Salles da Cunha, & Simonetti, 2013;Khuller, Bhatia, & Pless, 2003), which keeps the maximum number of nodes with the same degree as in the original graph, and the Minimum-Degree STP (Fürer & Raghavachari, 1990), where the maximum degree of the nodes in the tree is to be minimized. Still in this family, there is a sub-family of interesting problems which optimize a measure that depends only on the so-called branch vertices (alternatively branching nodes, branches), those nodes in the tree with a degree greater than two.…”