Mixed Unit Interval Bigraphs.

The class of intersection bigraphs of unit intervals of the real line whose ends may be open or closed is called mixed unit interval bigraphs. This class of bigraphs is a strict superclass of the class of unit interval bigraphs. We provide several infinite families of forbidden induced subgraphs of mixed unit interval bigraphs. We also pose a conjecture concerning characterization of mixed unit interval bigraphs and verify parts of it.