An Assertion Retrieval Algebra for Object Queries over Knowledge Bases
David Toman, Grant Weddell, Jeffrey Pound and Jiewen Wu
We consider a generalization of instance retrieval over knowledge bases that provides users with assertions in which descriptions of qualifying objects are given in addition to their identifiers. Notably, this involves a transfer of basic database paradigms involving caching and query rewriting in the context of an assertion retrieval algebra. We present an optimization framework for this algebra, with a focus on finding plans that avoid any need for general knowledge base reasoning at query execution time when such plans exist.