Circular-Arc Bigraphs and Its Subclasses



In this article, we obtain two new characterizations of circular-arc bigraphs. One of them is the representation of a circular-arc bigraph in terms of two two-clique circular-arc graphs while another one represents the same as a union of an interval bigraph and a Ferrers bigraph. Finally, we introduce the notions of proper and unit circular-arc bigraphs, characterize them and show that, as in the case of circular-arc graphs, unit circular-arc bigraphs form a proper subclass of the class of proper circular-arc bigraphs.