Query Algebra and Query Optimization for Concept Assertion Retrieval.
Jeffrey Pound, David Toman, Grant Weddell, Jiewen Wu · 2010
Abstract. We develop a query algebra that supports efficient assertion retrieval—a natural extension of instance retrieval. The algebra is based on previously developed techniques for indexing concept descriptions. We show how relational-style query processing, including the use of secondary indices, of multiple cascaded indices, and so on, can be used to improve query performance, and also develop general conditions that enable query reformulation. 1