مهدی جهانگیری

Finding a solution for the combinatorial optimization problems has always been important due to their applications. But most of them are NP-Complete and unsolvable in polynomial time. Therefore, the approxi- mation algorithms have been designed for them. One of these problems is total dominating set problem. In this paper, we present a new quadratic integer programming model for total dominating set problem and design an approximation method to nd a lower bound for total dominating number.