A new mathematics retrieval system

The Web contains a large collection of documents, some with mathematical expressions. Because mathematical expressions are objects with complex structures and rather few distinct symbols, conventional text retrieval systems are not very successful in mathematics retrieval. The lack of a definition for similarity between mathematical expressions, and the inadequacy of searching for exact matches only, makes the problem of mathematics retrieval even harder. As a result, the few existing mathematics retrieval systems are not very helpful in addressing users' needs. We propose a powerful query language for mathematical expressions that augments exact matching with approximate matching, but in a way that is controlled by the user. We also introduce a novel indexing scheme that scales well for large collections of expressions. Based on this indexing scheme, an efficient lookup algorithm is proposed.