 While in  Kraus et al. (1990)  the standard of deduction was classical propositional logic, in  Arieli and Avron (2000)  also nonclassical monotonic core logics and variants with multiple conclusions are considered. Various publications investigate the preferential and rational consequence relations in a first-order language (e.g.,  Lehmann and Magidor 1990,  Delgrande 1998,  Friedman et al. 2000).  