Wave Fronts in a Causality Violating Godel-Type Metric

The light rays and wave fronts in a linear class of the Godel-type metric are examined to reveal the causality-violating features of the space-time. Noncausal features demonstrated by the development of unusual wave front singularities are shown to be related to the nonmonotonic advance of time along the light rays, as measured by a system of observers at rest with respect to one another with synchronized clocks.