{"id":"https://openalex.org/W1983520140","doi":"https://doi.org/10.1080/00207160008804922","title":"On the expressive power of the relational algebra with partially ordered domains","display_name":"On the expressive power of the relational algebra with partially ordered domains","publication_year":2000,"publication_date":"2000-01-01","ids":{"openalex":"https://openalex.org/W1983520140","doi":"https://doi.org/10.1080/00207160008804922","mag":"1983520140"},"language":"en","primary_location":{"id":"doi:10.1080/00207160008804922","is_oa":false,"landing_page_url":"https://doi.org/10.1080/00207160008804922","pdf_url":null,"source":{"id":"https://openalex.org/S124867444","display_name":"International Journal of Computer Mathematics","issn_l":"0020-7160","issn":["0020-7160","1026-7425","1029-0265"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310320547","host_organization_name":"Taylor & Francis","host_organization_lineage":["https://openalex.org/P4310320547"],"host_organization_lineage_names":["Taylor & Francis"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"International Journal of Computer Mathematics","raw_type":"journal-article"},"type":"article","indexed_in":["crossref"],"open_access":{"is_oa":false,"oa_status":"closed","oa_url":null,"any_repository_has_fulltext":false},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5067034635","display_name":"Wilfred Ng","orcid":"https://orcid.org/0000-0001-6639-0521"},"institutions":[{"id":"https://openalex.org/I14243506","display_name":"Hong Kong Polytechnic University","ror":"https://ror.org/0030zas98","country_code":"HK","type":"education","lineage":["https://openalex.org/I14243506"]}],"countries":["HK"],"is_corresponding":true,"raw_author_name":"Wilfred Ng","raw_affiliation_strings":["Department of Computing , Hong Kong Polytechnic University ,","Department of Computing, Hong Kong Polytechnic University,"],"affiliations":[{"raw_affiliation_string":"Department of Computing , Hong Kong Polytechnic University ,","institution_ids":["https://openalex.org/I14243506"]},{"raw_affiliation_string":"Department of Computing, Hong Kong Polytechnic University,","institution_ids":["https://openalex.org/I14243506"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5015725705","display_name":"Mark Levene","orcid":"https://orcid.org/0000-0001-8632-4732"},"institutions":[{"id":"https://openalex.org/I124357947","display_name":"University of London","ror":"https://ror.org/04cw6st05","country_code":"GB","type":"education","lineage":["https://openalex.org/I124357947"]},{"id":"https://openalex.org/I4210160447","display_name":"Universidad de Londres","ror":"https://ror.org/054v4yq51","country_code":"MX","type":"education","lineage":["https://openalex.org/I4210160447"]},{"id":"https://openalex.org/I45129253","display_name":"University College London","ror":"https://ror.org/02jx3x895","country_code":"GB","type":"education","lineage":["https://openalex.org/I124357947","https://openalex.org/I45129253"]}],"countries":["GB","MX"],"is_corresponding":false,"raw_author_name":"Mark Levene","raw_affiliation_strings":["Department of Computer Science , University College London, University of London ,"],"affiliations":[{"raw_affiliation_string":"Department of Computer Science , University College London, University of London ,","institution_ids":["https://openalex.org/I45129253","https://openalex.org/I124357947","https://openalex.org/I4210160447"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5014473920","display_name":"Trevor Fenner","orcid":"https://orcid.org/0000-0002-4239-7574"},"institutions":[{"id":"https://openalex.org/I98259816","display_name":"Birkbeck, University of London","ror":"https://ror.org/02mb95055","country_code":"GB","type":"education","lineage":["https://openalex.org/I124357947","https://openalex.org/I98259816"]}],"countries":["GB"],"is_corresponding":false,"raw_author_name":"Trevor I. Fenner","raw_affiliation_strings":["Department of Computer Science , Birkbeck College, University of London ,"],"affiliations":[{"raw_affiliation_string":"Department of Computer Science , Birkbeck College, University of London ,","institution_ids":["https://openalex.org/I98259816"]}]}],"institutions":[],"countries_distinct_count":3,"institutions_distinct_count":3,"corresponding_author_ids":["https://openalex.org/A5067034635"],"corresponding_institution_ids":["https://openalex.org/I14243506"],"apc_list":null,"apc_paid":null,"fwci":1.2867,"has_fulltext":false,"cited_by_count":6,"citation_normalized_percentile":{"value":0.83781631,"is_in_top_1_percent":false,"is_in_top_10_percent":false},"cited_by_percentile_year":{"min":90,"max":94},"biblio":{"volume":"74","issue":"1","first_page":"53","last_page":"62"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10317","display_name":"Advanced Database Systems and Queries","score":0.9998000264167786,"subfield":{"id":"https://openalex.org/subfields/1705","display_name":"Computer Networks and Communications"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},"topics":[{"id":"https://openalex.org/T10317","display_name":"Advanced Database Systems and Queries","score":0.9998000264167786,"subfield":{"id":"https://openalex.org/subfields/1705","display_name":"Computer Networks and Communications"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T10215","display_name":"Semantic Web and Ontologies","score":0.9979000091552734,"subfield":{"id":"https://openalex.org/subfields/1702","display_name":"Artificial Intelligence"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}},{"id":"https://openalex.org/T11106","display_name":"Data Management and Algorithms","score":0.9958999752998352,"subfield":{"id":"https://openalex.org/subfields/1711","display_name":"Signal Processing"},"field":{"id":"https://openalex.org/fields/17","display_name":"Computer Science"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/mathematics","display_name":"Mathematics","score":0.7581103444099426},{"id":"https://openalex.org/keywords/expressive-power","display_name":"Expressive power","score":0.5978651642799377},{"id":"https://openalex.org/keywords/automorphism","display_name":"Automorphism","score":0.5281893014907837},{"id":"https://openalex.org/keywords/extension","display_name":"Extension (predicate logic)","score":0.5258820056915283},{"id":"https://openalex.org/keywords/power-set","display_name":"Power set","score":0.5175892114639282},{"id":"https://openalex.org/keywords/predicate","display_name":"Predicate (mathematical logic)","score":0.5120776295661926},{"id":"https://openalex.org/keywords/invariant","display_name":"Invariant (physics)","score":0.5062659978866577},{"id":"https://openalex.org/keywords/maximal-element","display_name":"Maximal element","score":0.5014667510986328},{"id":"https://openalex.org/keywords/total-order","display_name":"Total order","score":0.49601396918296814},{"id":"https://openalex.org/keywords/ordered-set","display_name":"Ordered set","score":0.4255432188510895},{"id":"https://openalex.org/keywords/set","display_name":"Set (abstract data type)","score":0.42159950733184814},{"id":"https://openalex.org/keywords/algebra-over-a-field","display_name":"Algebra over a field","score":0.4110032916069031},{"id":"https://openalex.org/keywords/discrete-mathematics","display_name":"Discrete mathematics","score":0.3713325262069702},{"id":"https://openalex.org/keywords/pure-mathematics","display_name":"Pure mathematics","score":0.3364275097846985},{"id":"https://openalex.org/keywords/partially-ordered-set","display_name":"Partially ordered set","score":0.29986387491226196},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.14131054282188416},{"id":"https://openalex.org/keywords/theoretical-computer-science","display_name":"Theoretical computer science","score":0.11741432547569275}],"concepts":[{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.7581103444099426},{"id":"https://openalex.org/C195818886","wikidata":"https://www.wikidata.org/wiki/Q5421724","display_name":"Expressive power","level":2,"score":0.5978651642799377},{"id":"https://openalex.org/C118712358","wikidata":"https://www.wikidata.org/wiki/Q782566","display_name":"Automorphism","level":2,"score":0.5281893014907837},{"id":"https://openalex.org/C2778029271","wikidata":"https://www.wikidata.org/wiki/Q5421931","display_name":"Extension (predicate logic)","level":2,"score":0.5258820056915283},{"id":"https://openalex.org/C100643331","wikidata":"https://www.wikidata.org/wiki/Q205170","display_name":"Power set","level":3,"score":0.5175892114639282},{"id":"https://openalex.org/C140146324","wikidata":"https://www.wikidata.org/wiki/Q1144319","display_name":"Predicate (mathematical logic)","level":2,"score":0.5120776295661926},{"id":"https://openalex.org/C190470478","wikidata":"https://www.wikidata.org/wiki/Q2370229","display_name":"Invariant (physics)","level":2,"score":0.5062659978866577},{"id":"https://openalex.org/C196773441","wikidata":"https://www.wikidata.org/wiki/Q1475294","display_name":"Maximal element","level":3,"score":0.5014667510986328},{"id":"https://openalex.org/C144901957","wikidata":"https://www.wikidata.org/wiki/Q369377","display_name":"Total order","level":3,"score":0.49601396918296814},{"id":"https://openalex.org/C2985459651","wikidata":"https://www.wikidata.org/wiki/Q474715","display_name":"Ordered set","level":2,"score":0.4255432188510895},{"id":"https://openalex.org/C177264268","wikidata":"https://www.wikidata.org/wiki/Q1514741","display_name":"Set (abstract data type)","level":2,"score":0.42159950733184814},{"id":"https://openalex.org/C136119220","wikidata":"https://www.wikidata.org/wiki/Q1000660","display_name":"Algebra over a field","level":2,"score":0.4110032916069031},{"id":"https://openalex.org/C118615104","wikidata":"https://www.wikidata.org/wiki/Q121416","display_name":"Discrete mathematics","level":1,"score":0.3713325262069702},{"id":"https://openalex.org/C202444582","wikidata":"https://www.wikidata.org/wiki/Q837863","display_name":"Pure mathematics","level":1,"score":0.3364275097846985},{"id":"https://openalex.org/C180645754","wikidata":"https://www.wikidata.org/wiki/Q474715","display_name":"Partially ordered set","level":2,"score":0.29986387491226196},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.14131054282188416},{"id":"https://openalex.org/C80444323","wikidata":"https://www.wikidata.org/wiki/Q2878974","display_name":"Theoretical computer science","level":1,"score":0.11741432547569275},{"id":"https://openalex.org/C37914503","wikidata":"https://www.wikidata.org/wiki/Q156495","display_name":"Mathematical physics","level":1,"score":0.0},{"id":"https://openalex.org/C199360897","wikidata":"https://www.wikidata.org/wiki/Q9143","display_name":"Programming language","level":1,"score":0.0}],"mesh":[],"locations_count":5,"locations":[{"id":"doi:10.1080/00207160008804922","is_oa":false,"landing_page_url":"https://doi.org/10.1080/00207160008804922","pdf_url":null,"source":{"id":"https://openalex.org/S124867444","display_name":"International Journal of Computer Mathematics","issn_l":"0020-7160","issn":["0020-7160","1026-7425","1029-0265"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310320547","host_organization_name":"Taylor & Francis","host_organization_lineage":["https://openalex.org/P4310320547"],"host_organization_lineage_names":["Taylor & Francis"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"International Journal of Computer Mathematics","raw_type":"journal-article"},{"id":"pmh:oai:CiteSeerX.psu:10.1.1.21.6182","is_oa":false,"landing_page_url":"http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.21.6182","pdf_url":null,"source":null,"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"http://www.dcs.bbk.ac.uk/~mark/download/pora.ps.gz","raw_type":"text"},{"id":"pmh:oai:CiteSeerX.psu:10.1.1.56.5787","is_oa":false,"landing_page_url":"http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.56.5787","pdf_url":null,"source":null,"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"ftp://cs.ucl.ac.uk/mlevene/pora.ps.gz","raw_type":"text"},{"id":"pmh:oai:CiteSeerX.psu:10.1.1.623.5844","is_oa":false,"landing_page_url":"http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.623.5844","pdf_url":null,"source":null,"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"https://www2.cse.ust.hk/~wilfred/paper/cmj01.pdf","raw_type":"text"},{"id":"pmh:oai:eprints.bbk.ac.uk.oai2:43541","is_oa":false,"landing_page_url":"https://eprints.bbk.ac.uk/id/eprint/43541/","pdf_url":null,"source":{"id":"https://openalex.org/S4306400466","display_name":"BIROn (Birkbeck, University of London)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I98259816","host_organization_name":"Birkbeck, University of London","host_organization_lineage":["https://openalex.org/I98259816"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"","raw_type":"Article"}],"best_oa_location":null,"sustainable_development_goals":[],"awards":[],"funders":[],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":11,"referenced_works":["https://openalex.org/W1493938990","https://openalex.org/W1497921804","https://openalex.org/W1983824794","https://openalex.org/W1992810975","https://openalex.org/W2056145119","https://openalex.org/W2087515863","https://openalex.org/W2105795736","https://openalex.org/W2161609549","https://openalex.org/W2162621793","https://openalex.org/W4230013745","https://openalex.org/W4246878928"],"related_works":["https://openalex.org/W3023810719","https://openalex.org/W4255072571","https://openalex.org/W4230449070","https://openalex.org/W1527353349","https://openalex.org/W2074631526","https://openalex.org/W2081430538","https://openalex.org/W4246572740","https://openalex.org/W2085370405","https://openalex.org/W86780670","https://openalex.org/W1983520140"],"abstract_inverted_index":{"Assuming":[0],"data":[1],"domains":[2],"are":[3,57],"partially":[4,9,95],"ordered,":[5],"we":[6],"define":[7],"the":[8,16,26,38,41,46,50,69,83],"ordered":[10,78,96],"relational":[11],"algebra":[12],"(PORA)":[13],"by":[14],"allowing":[15],"ordering":[17],"predicate":[18],"\u2291":[19],"to":[20,36],"be":[21],"used":[22],"in":[23],"formulae":[24],"of":[25,40,52,62,74],"selection":[27],"operator":[28],"\u03c3.":[29],"We":[30,80],"apply":[31],"Paredaens":[32],"and":[33,43,76,93,98],"Bancilhon's":[34],"Theorem":[35],"examine":[37],"expressiveness":[39],"PORA,":[42],"show":[44,99],"that":[45,100],"PORA":[47],"expresses":[48],"exactly":[49],"set":[51],"all":[53],"possible":[54],"relations":[55],"which":[56],"invariant":[58],"under":[59],"order-preserving":[60],"automorphisms":[61],"databases.":[63],"The":[64],"extension":[65],"is":[66,102],"consistent":[67],"with":[68],"two":[70],"important":[71],"extreme":[72],"cases":[73],"unordered":[75],"linearly":[77],"domains.":[79],"also":[81],"investigate":[82],"three":[84],"hierarchies":[85],"of:":[86],"(1)":[87],"computable":[88],"queries,":[89],"(2)":[90],"query":[91],"languages":[92],"(3)":[94],"domains,":[97],"there":[101],"a":[103],"one-to-one":[104],"correspondence":[105],"between":[106],"them.":[107]},"counts_by_year":[{"year":2012,"cited_by_count":1}],"updated_date":"2026-04-05T17:49:38.594831","created_date":"2025-10-10T00:00:00"}