Reintroducing the concept of ''force'' into relativity theory

Reintroducing ''forces'' into relativity theory may provide new insights and results. A look at the Kerr-Newmann geometry, and special cases of it, from this viewpoint indicates that there can be a short-range repulsion in general. This repulsion suggests that ''naked singularities'' may be physically feasible. There is a ''gravito-electric repulsion'' which would be important to consider in a grand-unification scheme of strong, weak and electromagnetic forces. (author)