Puzzling over Subsequence-Query Extensions: Disjunction and Generalised Gaps
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A query model for sequence data was introduced in [11] in the form of subsequence-queries with wildcards and gap-size constraints (swg-queries, for short). These queries consist of a pattern over an alphabet of variables and types, as well as a global window size and a number of local gap-size constraints. We propose two new extensions of swg-queries, which both enrich the expressive power of swg-queries in different ways: subsequence-queries with generalised gap-size constraints (swgg-queries, for short) and disjunctive subsequence-queries (dswg-queries, for short). We discuss a suitable characterisation of containment, a classical property considered in database theory, and adapt results concerning the discovery of swg-queries to both, swgg-queries and dswg-queries.
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