Another perspective on default reasoning
- Cite this article as:
- Lehmann, D. Ann Math Artif Intell (1995) 15: 61. doi:10.1007/BF01535841
The lexicographic closure of any given finite setD of normal defaults is defined. A conditional assertiona ❘∼b is in this lexicographic closure if, given the defaultsD and the facta, one would concludeb. The lexicographic closure is essentially a rational extension ofD, and of its rational closure, defined in a previous paper. It provides a logic of normal defaults that is different from the one proposed by R. Reiter and that is rich enough not to require the consideration of non-normal defaults. A large number of examples are provided to show that the lexicographic closure corresponds to the basic intuitions behind Reiter's logic of defaults.