Total 2-domination of proper interval graphs

Abstract

A set of vertices W of a graph G is a total k-dominating set when every vertex of G has at least k neighbors in W . In a recent article, Chiarelli et al. (Improved Algorithms for k-Domination and Total k-Domination in Proper Interval Graphs, Lecture Notes in Comput. Sci. 10856, 290-302, 2018) prove that a total k-dominating set can be computed in O(n 3k ) time when G is a proper interval graph with n vertices and m edges. In this note we reduce the time complexity to O(m) for k = 2.