@INPROCEEDINGS{Hustadt94c, AUTHOR = {Hustadt, Ullrich}, TITLE = {Do we need the closed-world assumption in knowledge representation}, BOOKTITLE = {Working Notes of the KI'94 Workshop: Reasoning about Structured Objects: Knowledge Representation Meets Databases (KRDB'94)}, EDITOR = {Baader, Franz and Buchheit, Martin and Jeusfeld, Manfred A. and Nutt, Werner}, SERIES = {Document}, VOLUME = {D-94-11}, PUBLISHER = {DFKI}, PAGES = {24--26}, PADDRESS = {Saarbr{\"u}cken, Germany}, PMONTH = nov, CADDRESS = {Saarbr{\"u}cken, Germany}, CYEAR = {1994}, CMONTH = sep # {~20--21}, ABSTRACT = {In this paper I want to focus on some principal differences between data models of database systems and knowledge representation languages. The data manipulation languages of data models are based on the closed-world, unique-name, and domain-closure assumption. Data manipulation languages and query languages of knowledge representation formalisms differ considerably in their underlying assumptions. They are based on the open-world, unique-name, and open-domain assumption. That means, that even if the data definition language and the data manipulation language of a database management system and a knowledge base management system would coincide, the results of data manipulations would differ. I present some examples that show the usefulness of closed-world inferences in natural language processing. Thus knowledge representation languages sticking to the open-world assumption seem to be insufficient for natural language processing.} }