  A dominating set of a graph $G$ is a set $D\subseteq V_G$ such that every
vertex in $V_G-D$ is adjacent to at least one vertex in $D$, and the domination
number $\gamma(G)$ of $G$ is the minimum cardinality of a dominating set of
$G$. In this paper we provide a new characterization of bipartite graphs whose
domination number is equal to the cardinality of its smaller partite set. Our
characterization is based upon a new graph operation.
