Direct Product Decompositions of Lattices, Closures and Relation Schemes

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dc.contributor.authorLibkin, Leonid
dc.date2023-05-17T01:10:32.000
dc.date.accessioned2023-05-22T12:56:11Z
dc.date.available2023-05-22T12:56:11Z
dc.date.issued1990-11-01
dc.date.submitted2007-08-14T07:55:54-07:00
dc.description.abstractIn this paper we study direct product decompositions of closure operations and lattices of closed sets. We characterize direct product decompositions of lattices of closed sets in terms of closure operations, and find those decompositions of lattices which correspond to the decompositions of closures. If a closure on a finite set is represented by its implication base (i.e. a binary relation on a powerset), we construct a polynomial algorithm to find its direct product decompositions. The main characterization theorem is also applied to define direct product decompositions of relational database schemes and to find out what properties of relational databases and schemes are preserved under decompositions.
dc.description.commentsUniversity of Pennsylvania Department of Computer and Information Science Technical Report No. MS-CIS-90-85.
dc.identifier.urihttps://repository.upenn.edu/handle/20.500.14332/7361
dc.legacy.articleid1445
dc.legacy.fulltexturlhttps://repository.upenn.edu/cgi/viewcontent.cgi?article=1445&context=cis_reports&unstamped=1
dc.source.issue432
dc.source.journalTechnical Reports (CIS)
dc.source.statuspublished
dc.titleDirect Product Decompositions of Lattices, Closures and Relation Schemes
dc.typeReport
digcom.identifiercis_reports/432
digcom.identifier.contextkey339355
digcom.identifier.submissionpathcis_reports/432
digcom.typereport
dspace.entity.typePublication
upenn.schoolDepartmentCenterTechnical Reports (CIS)
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