RT journal article T1 A constructive characterization of vertex cover Roman trees A1 Cabrera Martínez, Abel A1 Kuziak, Dorota A1 González Yero, Ismael A2 Matemáticas K1 Roman domination K1 outer-independent Roman domination K1 vertex cover K1 vertex independence K1 trees AB A Roman dominating function on a graph G = (V (G), E (G)) is a function f : V (G) -> {0, 1, 2} satisfying the condition that every vertex u for which f (u) = 0 is adjacent to at least one vertex v for which f (v) = 2. The Roman dominating function f is an outer-independent Roman dominating function on G if the set of vertices labeled with zero under f is an independent set. The outer-independent Roman domination number gamma(oiR) (G) is the minimum weight w(f ) = Sigma(v is an element of V), ((G)) f(v) of any outer-independent Roman dominating function f of G. A vertex cover of a graph G is a set of vertices that covers all the edges of G. The minimum cardinality of a vertex cover is denoted by alpha(G). A graph G is a vertex cover Roman graph if gamma(oiR) (G) = 2 alpha(G). A constructive characterization of the vertex cover Roman trees is given in this article. PB UNIV ZIELONA GORA SN 1234-3099 YR 2020 FD 2020 LK http://hdl.handle.net/10498/24150 UL http://hdl.handle.net/10498/24150 LA eng DS Repositorio Institucional de la Universidad de Cádiz RD 10-may-2026