The logical meaning of Expansion
<|reference_start|>The logical meaning of Expansion: The Expansion property considered by researchers in Social Choice is shown to correspond to a logical property of nonmonotonic consequence relations that is the {\em pure}, i.e., not involving connectives, version of a previously known weak rationality condition. The assumption that the union of two definable sets of models is definable is needed for the soundness part of the result.<|reference_end|>
@article{lehmann2002the,
    title={The logical meaning of Expansion},
    author={Daniel Lehmann},
    journal={arXiv preprint arXiv:cs/0202033},
    year={2002},
    archivePrefix={arXiv},
    eprint={cs/0202033},
    primaryClass={cs.AI}
}