Dempster-Shafer ranges for an RMS

Doyle´s reason maintenance system (RMS) was invented to emulate certain aspects of human reasoning (J. Doyle, 1979). In particular, an RMS can support reasoning in the face of incomplete and inconsistent knowledge. Non-monotonic logic (NML) was devised to describe the workings of such a system. A significant property of NML is that a theory may have several conflicting extensions. These may be envisaged as different ways of applying internally consistent sets of conflicting defaults. Doyle suggested that the operation of the RMS might be enhanced by adding degrees of belief to the RMS in order to choose between different extensions. The author proposes that Dempster-Shafer (DS) belief ranges are well suited to this task and that they have further properties useful to a common-sense reasoning system (G. Shafer, 1976).