Reasoning with Uncertainty by Non-Deterministic and Distance-Based Semantics Ofer Arieli ABSTRACT We introduce a modular framework for reasoning with incomplete and inconsistent information. This framework is composed of non-deterministic semantic structures and distance-based considerations. The combination of these two principles leads to a variety of entailment relations that can be used for reasoning about non-deterministic phenomena and are inconsistency-tolerant. We investigate the basic properties of these entailments, as well as some of their computational aspects, and demonstrate their usefulness in the context of model-based diagnostic systems. This is a joint work with Anna Zamansky.