On a Class of Graphs with Large Total Domination Number
Let $gamma(G)$ and $gamma_t(G)$ denote the domination number and the total domination number, Fashion Print Headstall and Breast Collar Sets respectively, of a graph $G$ with no isolated vertices.It is well-known that $gamma_t(G) leq 2gamma(G)$.We provide a characterization of a large family of graphs (including chordal graphs) satisfying $gamma_t(