Alternative Phrases and Natural Language Information Retrieval 
 This paper presents a formal analysis for a large class of words called alternative markers , which includes other (than) , such (as) , and besides . These words appear frequently enough in dialog to warrant serious attention , yet present natural language search engines perform poorly on queries containing them. I show that the performance of a search engine can be improved dramatically by incorporating an approximation of the formal analysis that is compatible with the search engine 's operational semantics . The value of this approach is that as the operational semantics of natural language applications improve, even larger improvements are possible. 