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M. Scherfner

Publications and source records attributed to M. Scherfner.

2 recordsLinked to original sources

Geometric Analysis of Ori-type Spacetimes

In 1993 A. Ori \cite{Ori93} presented spacetimes violating the chronology condition in order to answer the question whether a time machine construction has to violate the weak energy condition or not. Later, in 2005 \cite{Ori05}, he constructed a class of time machine solutions with compact vacuum core. Both classes include an interesting global structure and it is possible to obtain closed timelike curves. Besides we focus on the geometric structure, in particular symmetries and geodesics, if feasible, and visualize several aspects.

gr-qc

On Spacetimes with Given Kinematical Invariants: Construction and Examples

We present a useful method for the construction of cosmological models by solving the differential equations arising from calculating the kinematical invariants (shear, rotation, expansion and acceleration) of an observer field in proper time description. As an application of our method we present two generalizations of the Gödel spacetime that follow naturally from our approach.

gr-qc