We generalize a theorem on the relation of the Extended Closed World Assumption (ECWA) to circumscription due to Gelfond, Przymusinska and Przymusinski, and give a simple proof of the generalized result.

PS

Annals of Mathematics and Artificial Intelligence, Vol. 14 (1995), pp. 269-274.

@ARTICLE{lif95b, title={ECWA Made Easy}, author={Vladimir Lifschitz}, volume={14}, journal={Annals of Mathematics and Artificial Intelligence}, pages={269-274}, url="http://www.cs.utexas.edu/users/ai-lab?lif95b", year={1995} }