{"id":"https://openalex.org/W2074385562","doi":"https://doi.org/10.1145/1055558.1055585","title":"Conjunctive queries over trees","display_name":"Conjunctive queries over trees","publication_year":2004,"publication_date":"2004-06-14","ids":{"openalex":"https://openalex.org/W2074385562","doi":"https://doi.org/10.1145/1055558.1055585","mag":"2074385562"},"language":"en","primary_location":{"id":"doi:10.1145/1055558.1055585","is_oa":false,"landing_page_url":"https://doi.org/10.1145/1055558.1055585","pdf_url":null,"source":null,"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems","raw_type":"proceedings-article"},"type":"article","indexed_in":["crossref"],"open_access":{"is_oa":true,"oa_status":"green","oa_url":"http://infoscience.epfl.ch/record/166880","any_repository_has_fulltext":true},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5050151740","display_name":"Georg Gottlob","orcid":"https://orcid.org/0000-0002-2353-5230"},"institutions":[{"id":"https://openalex.org/I145847075","display_name":"TU Wien","ror":"https://ror.org/04d836q62","country_code":"AT","type":"education","lineage":["https://openalex.org/I145847075"]}],"countries":["AT"],"is_corresponding":true,"raw_author_name":"Georg Gottlob","raw_affiliation_strings":["DBAI, TU Wien, Austria"],"affiliations":[{"raw_affiliation_string":"DBAI, TU Wien, Austria","institution_ids":["https://openalex.org/I145847075"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5101903922","display_name":"Christoph Koch","orcid":"https://orcid.org/0000-0002-9130-7205"},"institutions":[{"id":"https://openalex.org/I145847075","display_name":"TU Wien","ror":"https://ror.org/04d836q62","country_code":"AT","type":"education","lineage":["https://openalex.org/I145847075"]}],"countries":["AT"],"is_corresponding":false,"raw_author_name":"Christoph Koch","raw_affiliation_strings":["DBAI, TU Wien, Austria"],"affiliations":[{"raw_affiliation_string":"DBAI, TU Wien, Austria","institution_ids":["https://openalex.org/I145847075"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5109699155","display_name":"Klaus U. Schulz","orcid":null},"institutions":[{"id":"https://openalex.org/I8204097","display_name":"Ludwig-Maximilians-Universit\u00e4t M\u00fcnchen","ror":"https://ror.org/05591te55","country_code":"DE","type":"education","lineage":["https://openalex.org/I8204097"]}],"countries":["DE"],"is_corresponding":false,"raw_author_name":"Klaus U. Schulz","raw_affiliation_strings":["CIS, LMU M\u00fcnchen, Germany"],"affiliations":[{"raw_affiliation_string":"CIS, LMU M\u00fcnchen, Germany","institution_ids":["https://openalex.org/I8204097"]}]}],"institutions":[],"countries_distinct_count":2,"institutions_distinct_count":3,"corresponding_author_ids":["https://openalex.org/A5050151740"],"corresponding_institution_ids":["https://openalex.org/I145847075"],"apc_list":null,"apc_paid":null,"fwci":8.9744,"has_fulltext":false,"cited_by_count":54,"citation_normalized_percentile":{"value":0.97848589,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":{"min":89,"max":94},"biblio":{"volume":null,"issue":null,"first_page":"189","last_page":"200"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10317","display_name":"Advanced Database Systems and Queries","score":0.9988999962806702,"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":0.9988999962806702,"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/T11106","display_name":"Data Management and Algorithms","score":0.9988999962806702,"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"}},{"id":"https://openalex.org/T11596","display_name":"Constraint Satisfaction and Optimization","score":0.9987999796867371,"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"}}],"keywords":[{"id":"https://openalex.org/keywords/conjunctive-query","display_name":"Conjunctive query","score":0.9475911855697632},{"id":"https://openalex.org/keywords/xpath","display_name":"XPath","score":0.7549358010292053},{"id":"https://openalex.org/keywords/boolean-conjunctive-query","display_name":"Boolean conjunctive query","score":0.7443241477012634},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.6494978666305542},{"id":"https://openalex.org/keywords/unary-operation","display_name":"Unary operation","score":0.6163932085037231},{"id":"https://openalex.org/keywords/theoretical-computer-science","display_name":"Theoretical computer science","score":0.5664258599281311},{"id":"https://openalex.org/keywords/query-language","display_name":"Query language","score":0.5515230298042297},{"id":"https://openalex.org/keywords/query-optimization","display_name":"Query optimization","score":0.5313414335250854},{"id":"https://openalex.org/keywords/conjunctive-normal-form","display_name":"Conjunctive normal form","score":0.4961920380592346},{"id":"https://openalex.org/keywords/tree","display_name":"Tree (set theory)","score":0.46087056398391724},{"id":"https://openalex.org/keywords/range-query","display_name":"Range query (database)","score":0.45543015003204346},{"id":"https://openalex.org/keywords/xml","display_name":"XML","score":0.45091089606285095},{"id":"https://openalex.org/keywords/expressive-power","display_name":"Expressive power","score":0.44995975494384766},{"id":"https://openalex.org/keywords/set","display_name":"Set (abstract data type)","score":0.4439208209514618},{"id":"https://openalex.org/keywords/spatial-query","display_name":"Spatial query","score":0.44214528799057007},{"id":"https://openalex.org/keywords/time-complexity","display_name":"Time complexity","score":0.4354937672615051},{"id":"https://openalex.org/keywords/treewidth","display_name":"Treewidth","score":0.41796478629112244},{"id":"https://openalex.org/keywords/web-query-classification","display_name":"Web query classification","score":0.4170342683792114},{"id":"https://openalex.org/keywords/mathematics","display_name":"Mathematics","score":0.33521100878715515},{"id":"https://openalex.org/keywords/discrete-mathematics","display_name":"Discrete mathematics","score":0.30317264795303345},{"id":"https://openalex.org/keywords/algorithm","display_name":"Algorithm","score":0.2374277412891388},{"id":"https://openalex.org/keywords/information-retrieval","display_name":"Information retrieval","score":0.23124155402183533},{"id":"https://openalex.org/keywords/relational-database","display_name":"Relational database","score":0.23055142164230347},{"id":"https://openalex.org/keywords/combinatorics","display_name":"Combinatorics","score":0.22821950912475586},{"id":"https://openalex.org/keywords/programming-language","display_name":"Programming language","score":0.2079782485961914},{"id":"https://openalex.org/keywords/web-search-query","display_name":"Web search query","score":0.15959039330482483},{"id":"https://openalex.org/keywords/graph","display_name":"Graph","score":0.10361534357070923}],"concepts":[{"id":"https://openalex.org/C65647387","wikidata":"https://www.wikidata.org/wiki/Q1781706","display_name":"Conjunctive query","level":3,"score":0.9475911855697632},{"id":"https://openalex.org/C2780213375","wikidata":"https://www.wikidata.org/wiki/Q16340","display_name":"XPath","level":4,"score":0.7549358010292053},{"id":"https://openalex.org/C24755975","wikidata":"https://www.wikidata.org/wiki/Q4943354","display_name":"Boolean conjunctive query","level":5,"score":0.7443241477012634},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.6494978666305542},{"id":"https://openalex.org/C78023250","wikidata":"https://www.wikidata.org/wiki/Q657596","display_name":"Unary operation","level":2,"score":0.6163932085037231},{"id":"https://openalex.org/C80444323","wikidata":"https://www.wikidata.org/wiki/Q2878974","display_name":"Theoretical computer science","level":1,"score":0.5664258599281311},{"id":"https://openalex.org/C192028432","wikidata":"https://www.wikidata.org/wiki/Q845739","display_name":"Query language","level":2,"score":0.5515230298042297},{"id":"https://openalex.org/C157692150","wikidata":"https://www.wikidata.org/wiki/Q2919848","display_name":"Query optimization","level":2,"score":0.5313414335250854},{"id":"https://openalex.org/C16221470","wikidata":"https://www.wikidata.org/wiki/Q846564","display_name":"Conjunctive normal form","level":2,"score":0.4961920380592346},{"id":"https://openalex.org/C113174947","wikidata":"https://www.wikidata.org/wiki/Q2859736","display_name":"Tree (set theory)","level":2,"score":0.46087056398391724},{"id":"https://openalex.org/C136736807","wikidata":"https://www.wikidata.org/wiki/Q818943","display_name":"Range query (database)","level":5,"score":0.45543015003204346},{"id":"https://openalex.org/C8797682","wikidata":"https://www.wikidata.org/wiki/Q2115","display_name":"XML","level":2,"score":0.45091089606285095},{"id":"https://openalex.org/C195818886","wikidata":"https://www.wikidata.org/wiki/Q5421724","display_name":"Expressive power","level":2,"score":0.44995975494384766},{"id":"https://openalex.org/C177264268","wikidata":"https://www.wikidata.org/wiki/Q1514741","display_name":"Set (abstract data type)","level":2,"score":0.4439208209514618},{"id":"https://openalex.org/C172722865","wikidata":"https://www.wikidata.org/wiki/Q2302053","display_name":"Spatial query","level":5,"score":0.44214528799057007},{"id":"https://openalex.org/C311688","wikidata":"https://www.wikidata.org/wiki/Q2393193","display_name":"Time complexity","level":2,"score":0.4354937672615051},{"id":"https://openalex.org/C132569581","wikidata":"https://www.wikidata.org/wiki/Q5067368","display_name":"Treewidth","level":5,"score":0.41796478629112244},{"id":"https://openalex.org/C118689300","wikidata":"https://www.wikidata.org/wiki/Q7978614","display_name":"Web query classification","level":4,"score":0.4170342683792114},{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.33521100878715515},{"id":"https://openalex.org/C118615104","wikidata":"https://www.wikidata.org/wiki/Q121416","display_name":"Discrete mathematics","level":1,"score":0.30317264795303345},{"id":"https://openalex.org/C11413529","wikidata":"https://www.wikidata.org/wiki/Q8366","display_name":"Algorithm","level":1,"score":0.2374277412891388},{"id":"https://openalex.org/C23123220","wikidata":"https://www.wikidata.org/wiki/Q816826","display_name":"Information retrieval","level":1,"score":0.23124155402183533},{"id":"https://openalex.org/C5655090","wikidata":"https://www.wikidata.org/wiki/Q192588","display_name":"Relational database","level":2,"score":0.23055142164230347},{"id":"https://openalex.org/C114614502","wikidata":"https://www.wikidata.org/wiki/Q76592","display_name":"Combinatorics","level":1,"score":0.22821950912475586},{"id":"https://openalex.org/C199360897","wikidata":"https://www.wikidata.org/wiki/Q9143","display_name":"Programming language","level":1,"score":0.2079782485961914},{"id":"https://openalex.org/C164120249","wikidata":"https://www.wikidata.org/wiki/Q995982","display_name":"Web search query","level":3,"score":0.15959039330482483},{"id":"https://openalex.org/C132525143","wikidata":"https://www.wikidata.org/wiki/Q141488","display_name":"Graph","level":2,"score":0.10361534357070923},{"id":"https://openalex.org/C97854310","wikidata":"https://www.wikidata.org/wiki/Q19541","display_name":"Search engine","level":2,"score":0.0},{"id":"https://openalex.org/C203776342","wikidata":"https://www.wikidata.org/wiki/Q1378376","display_name":"Line graph","level":3,"score":0.0},{"id":"https://openalex.org/C111919701","wikidata":"https://www.wikidata.org/wiki/Q9135","display_name":"Operating system","level":1,"score":0.0},{"id":"https://openalex.org/C43517604","wikidata":"https://www.wikidata.org/wiki/Q7144893","display_name":"Pathwidth","level":4,"score":0.0},{"id":"https://openalex.org/C55348073","wikidata":"https://www.wikidata.org/wiki/Q595926","display_name":"XML validation","level":3,"score":0.0}],"mesh":[],"locations_count":2,"locations":[{"id":"doi:10.1145/1055558.1055585","is_oa":false,"landing_page_url":"https://doi.org/10.1145/1055558.1055585","pdf_url":null,"source":null,"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Proceedings of the twenty-third ACM SIGMOD-SIGACT-SIGART symposium on Principles of database systems","raw_type":"proceedings-article"},{"id":"pmh:oai:infoscience.epfl.ch:166880","is_oa":true,"landing_page_url":"http://infoscience.epfl.ch/record/166880","pdf_url":null,"source":{"id":"https://openalex.org/S4306400487","display_name":"Infoscience (Ecole Polytechnique F\u00e9d\u00e9rale de Lausanne)","issn_l":null,"issn":null,"is_oa":true,"is_in_doaj":false,"is_core":false,"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"","raw_type":"Text"}],"best_oa_location":{"id":"pmh:oai:infoscience.epfl.ch:166880","is_oa":true,"landing_page_url":"http://infoscience.epfl.ch/record/166880","pdf_url":null,"source":{"id":"https://openalex.org/S4306400487","display_name":"Infoscience (Ecole Polytechnique F\u00e9d\u00e9rale de Lausanne)","issn_l":null,"issn":null,"is_oa":true,"is_in_doaj":false,"is_core":false,"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"","raw_type":"Text"},"sustainable_development_goals":[],"awards":[{"id":"https://openalex.org/G6052429835","display_name":null,"funder_award_id":"(DFG)","funder_id":"https://openalex.org/F4320320879","funder_display_name":"Deutsche Forschungsgemeinschaft"},{"id":"https://openalex.org/G6225918512","display_name":null,"funder_award_id":"project Z","funder_id":"https://openalex.org/F4320320879","funder_display_name":"Deutsche Forschungsgemeinschaft"},{"id":"https://openalex.org/G7082289709","display_name":null,"funder_award_id":"project Z2","funder_id":"https://openalex.org/F4320320879","funder_display_name":"Deutsche Forschungsgemeinschaft"}],"funders":[{"id":"https://openalex.org/F4320320879","display_name":"Deutsche Forschungsgemeinschaft","ror":"https://ror.org/018mejw64"},{"id":"https://openalex.org/F4320321181","display_name":"Austrian Science Fund","ror":"https://ror.org/013tf3c58"}],"has_content":{"pdf":false,"grobid_xml":false},"content_urls":null,"referenced_works_count":42,"referenced_works":["https://openalex.org/W52840101","https://openalex.org/W655258421","https://openalex.org/W1482193060","https://openalex.org/W1489366126","https://openalex.org/W1525848106","https://openalex.org/W1558832481","https://openalex.org/W1572710747","https://openalex.org/W1593879680","https://openalex.org/W1599833144","https://openalex.org/W1716100575","https://openalex.org/W1816466119","https://openalex.org/W1825515612","https://openalex.org/W1847375251","https://openalex.org/W1968934723","https://openalex.org/W1979514837","https://openalex.org/W2004717713","https://openalex.org/W2026745535","https://openalex.org/W2046652577","https://openalex.org/W2065197261","https://openalex.org/W2070632872","https://openalex.org/W2079107830","https://openalex.org/W2086916741","https://openalex.org/W2115309483","https://openalex.org/W2115822498","https://openalex.org/W2122225808","https://openalex.org/W2124102576","https://openalex.org/W2134483537","https://openalex.org/W2134826526","https://openalex.org/W2148210463","https://openalex.org/W2160442532","https://openalex.org/W2160888032","https://openalex.org/W2166566648","https://openalex.org/W2169602474","https://openalex.org/W2170477095","https://openalex.org/W2337098149","https://openalex.org/W2998605285","https://openalex.org/W4285719527","https://openalex.org/W6602175484","https://openalex.org/W6628898632","https://openalex.org/W6634746015","https://openalex.org/W6635665063","https://openalex.org/W6990188669"],"related_works":["https://openalex.org/W2403400424","https://openalex.org/W2063039776","https://openalex.org/W2469887214","https://openalex.org/W4295792406","https://openalex.org/W2952721883","https://openalex.org/W95894471","https://openalex.org/W2899614929","https://openalex.org/W4388937114","https://openalex.org/W1968050632","https://openalex.org/W3209793312"],"abstract_inverted_index":{"We":[0,67,149],"study":[1,130],"the":[2,15,34,62,88,92,122,131,142],"complexity":[3],"and":[4,27,64,138],"expressive":[5,143],"power":[6,144],"of":[7,33,55,91,105,133,145,147,166,178],"conjunctive":[8,46,78,134,154,168],"queries":[9,47,79,135],"over":[10,48,136],"unranked":[11],"labeled":[12],"trees,":[13],"where":[14],"tree":[16],"structure":[17],"are":[18,118],"represented":[19],"using":[20,121],"\"axis":[21],"relations\"":[22],"such":[23],"as":[24,37,39],"\"child\",":[25],"\"descendant\",":[26],"\"following\"":[28],"(we":[29],"consider":[30],"a":[31,52,69,164],"superset":[32],"XPath":[35],"axes)":[36],"well":[38],"unary":[40],"relations":[41],"for":[42,71,76,94,107,152],"node":[43],"labels.":[44],"(Cyclic)":[45],"trees":[49,75,137],"occur":[50],"in":[51,112,172],"wide":[53],"range":[54],"data":[56],"management":[57],"scenarios":[58],"related":[59],"to":[60,141],"XML,":[61],"Web,":[63],"computational":[65],"linguistics.":[66],"establish":[68],"framework":[70],"characterizing":[72],"structures":[73],"representing":[74],"which":[77,108],"can":[80],"be":[81],"evaluated":[82],"efficiently.":[83],"Then":[84],"we":[85,99,129],"completely":[86],"chart":[87],"tractability":[89],"frontier":[90],"problem":[93],"our":[95,126],"axis":[96],"relations,":[97],"i.e.,":[98],"find":[100],"all":[101],"subset":[102],"maximal":[103],"sets":[104],"axes":[106],"query":[109,162,175],"evaluation":[110],"is":[111,157,176],"polynomial":[113,179],"time.":[114],"All":[115],"polynomial-time":[116],"results":[117],"obtained":[119],"immediately":[120],"proof":[123],"techniques":[124],"from":[125],"framework.":[127],"Finally,":[128],"expressiveness":[132],"compare":[139],"it":[140],"fragments":[146],"XPath.":[148],"show":[150],"that":[151,171],"each":[153],"query,":[155],"there":[156],"an":[158],"equivalent":[159],"acyclic":[160,167],"positive":[161],"(i.e.,":[163],"set":[165],"queries),":[169],"but":[170],"general":[173],"this":[174],"not":[177],"size.":[180]},"counts_by_year":[{"year":2017,"cited_by_count":1},{"year":2014,"cited_by_count":1},{"year":2013,"cited_by_count":1}],"updated_date":"2026-04-10T15:06:20.359241","created_date":"2025-10-10T00:00:00"}
