Quasi-metrics, Similarities and Searches: aspects of geometry of protein datasets

dc.creatorStojmirovic, Aleksandar
dc.date2008-10-30
dc.date.accessioned2026-07-07T10:14:07Z
dc.date.available2026-07-07T10:14:07Z
dc.descriptionA quasi-metric is a distance function which satisfies the triangle inequality but is not symmetric: it can be thought of as an asymmetric metric. The central result of this thesis, developed in Chapter 3, is that a natural correspondence exists between similarity measures between biological (nucleotide or protein) sequences and quasi-metrics. Chapter 2 presents basic concepts of the theory of quasi-metric spaces and introduces a new examples of them: the universal countable rational quasi-metric space and its bicompletion, the universal bicomplete separable quasi-metric space. Chapter 4 is dedicated to development of a notion of the quasi-metric space with Borel probability measure, or pq-space. The main result of this chapter indicates that `a high dimensional quasi-metric space is close to being a metric space'. Chapter 5 investigates the geometric aspects of the theory of database similarity search in the context of quasi-metrics. The results about $pq$-spaces are used to produce novel theoretical bounds on performance of indexing schemes. Finally, the thesis presents some biological applications. Chapter 6 introduces FSIndex, an indexing scheme that significantly accelerates similarity searches of short protein fragment datasets. Chapter 7 presents the prototype of the system for discovery of short functional protein motifs called PFMFind, which relies on FSIndex for similarity searches.
dc.description299 pages, 44 figures, 10 tables, 9 algorithms. PhD thesis in mathematics defended in May 2005 at the Victoria University of Wellington, Wellington, New Zealand (supervisors: Prof. Vladimir Pestov and Dr. Bill Jordan)
dc.identifierhttps://arxiv.org/abs/0810.5407
dc.identifierhttp://arxiv.org/abs/0810.5407
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/172771
dc.subjectInformation Retrieval
dc.subjectGeneral Topology
dc.subjectQuantitative Methods
dc.titleQuasi-metrics, Similarities and Searches: aspects of geometry of protein datasets
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