{"id":"https://openalex.org/W2908453256","doi":"https://doi.org/10.1007/s00224-020-10002-z","title":"Characterizing Tractability of Simple Well-Designed Pattern Trees with Projection","display_name":"Characterizing Tractability of Simple Well-Designed Pattern Trees with Projection","publication_year":2020,"publication_date":"2020-09-10","ids":{"openalex":"https://openalex.org/W2908453256","doi":"https://doi.org/10.1007/s00224-020-10002-z","mag":"2908453256","pmid":"https://pubmed.ncbi.nlm.nih.gov/33568963"},"language":"en","primary_location":{"id":"doi:10.1007/s00224-020-10002-z","is_oa":true,"landing_page_url":"https://doi.org/10.1007/s00224-020-10002-z","pdf_url":"https://link.springer.com/content/pdf/10.1007/s00224-020-10002-z.pdf","source":{"id":"https://openalex.org/S4210177266","display_name":"Theory of Computing Systems","issn_l":"1432-4350","issn":["1432-4350","1433-0490"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310319900","host_organization_name":"Springer Science+Business Media","host_organization_lineage":["https://openalex.org/P4310319900","https://openalex.org/P4310319965"],"host_organization_lineage_names":["Springer Science+Business Media","Springer Nature"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Theory of Computing Systems","raw_type":"journal-article"},"type":"article","indexed_in":["crossref","datacite","pubmed"],"open_access":{"is_oa":true,"oa_status":"hybrid","oa_url":"https://link.springer.com/content/pdf/10.1007/s00224-020-10002-z.pdf","any_repository_has_fulltext":true},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5033060526","display_name":"Stefan Mengel","orcid":"https://orcid.org/0000-0003-1386-8784"},"institutions":[{"id":"https://openalex.org/I1294671590","display_name":"Centre National de la Recherche Scientifique","ror":"https://ror.org/02feahw73","country_code":"FR","type":"government","lineage":["https://openalex.org/I1294671590"]},{"id":"https://openalex.org/I4210115519","display_name":"Centre de Recherche en Informatique","ror":"https://ror.org/020cdve92","country_code":"FR","type":"facility","lineage":["https://openalex.org/I190752583","https://openalex.org/I2746051580","https://openalex.org/I4210091621","https://openalex.org/I4210115519","https://openalex.org/I70768539"]},{"id":"https://openalex.org/I44563897","display_name":"Universit\u00e9 d'Artois","ror":"https://ror.org/053x9s498","country_code":"FR","type":"education","lineage":["https://openalex.org/I44563897"]}],"countries":["FR"],"is_corresponding":false,"raw_author_name":"Stefan Mengel","raw_affiliation_strings":["CRIL, CNRS & Universit\u00e9 d'Artois, Lens, France","Centre de Recherche en Informatique de Lens"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"CRIL, CNRS & Universit\u00e9 d'Artois, Lens, France","institution_ids":["https://openalex.org/I1294671590","https://openalex.org/I44563897"]},{"raw_affiliation_string":"Centre de Recherche en Informatique de Lens","institution_ids":["https://openalex.org/I4210115519"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5088801808","display_name":"Sebastian Skritek","orcid":"https://orcid.org/0000-0003-3054-7683"},"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":"Sebastian Skritek","raw_affiliation_strings":["Faculty of Informatics, TU Wien, Vienna, Austria"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Faculty of Informatics, TU Wien, Vienna, Austria","institution_ids":["https://openalex.org/I145847075"]}]}],"institutions":[],"countries_distinct_count":2,"institutions_distinct_count":4,"corresponding_author_ids":["https://openalex.org/A5088801808"],"corresponding_institution_ids":["https://openalex.org/I145847075"],"apc_list":{"value":2890,"currency":"USD","value_usd":2890},"apc_paid":{"value":2890,"currency":"USD","value_usd":2890},"fwci":0.0,"has_fulltext":true,"cited_by_count":0,"citation_normalized_percentile":{"value":0.00982807,"is_in_top_1_percent":false,"is_in_top_10_percent":false},"cited_by_percentile_year":null,"biblio":{"volume":"65","issue":"1","first_page":"3","last_page":"41"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T10317","display_name":"Advanced Database Systems and Queries","score":0.3476000130176544,"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":0.3476000130176544,"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/T11269","display_name":"Algorithms and Data Compression","score":0.08460000157356262,"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/T11450","display_name":"Model-Driven Software Engineering Techniques","score":0.05739999935030937,"subfield":{"id":"https://openalex.org/subfields/1712","display_name":"Software"},"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/simple","display_name":"Simple (philosophy)","score":0.7959576845169067},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.6339167356491089},{"id":"https://openalex.org/keywords/projection","display_name":"Projection (relational algebra)","score":0.5816145539283752},{"id":"https://openalex.org/keywords/artificial-intelligence","display_name":"Artificial intelligence","score":0.3727223575115204},{"id":"https://openalex.org/keywords/algorithm","display_name":"Algorithm","score":0.3567556142807007},{"id":"https://openalex.org/keywords/mathematical-optimization","display_name":"Mathematical optimization","score":0.32552120089530945},{"id":"https://openalex.org/keywords/mathematics","display_name":"Mathematics","score":0.2939910888671875}],"concepts":[{"id":"https://openalex.org/C2780586882","wikidata":"https://www.wikidata.org/wiki/Q7520643","display_name":"Simple (philosophy)","level":2,"score":0.7959576845169067},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.6339167356491089},{"id":"https://openalex.org/C57493831","wikidata":"https://www.wikidata.org/wiki/Q3134666","display_name":"Projection (relational algebra)","level":2,"score":0.5816145539283752},{"id":"https://openalex.org/C154945302","wikidata":"https://www.wikidata.org/wiki/Q11660","display_name":"Artificial intelligence","level":1,"score":0.3727223575115204},{"id":"https://openalex.org/C11413529","wikidata":"https://www.wikidata.org/wiki/Q8366","display_name":"Algorithm","level":1,"score":0.3567556142807007},{"id":"https://openalex.org/C126255220","wikidata":"https://www.wikidata.org/wiki/Q141495","display_name":"Mathematical optimization","level":1,"score":0.32552120089530945},{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.2939910888671875},{"id":"https://openalex.org/C138885662","wikidata":"https://www.wikidata.org/wiki/Q5891","display_name":"Philosophy","level":0,"score":0.0},{"id":"https://openalex.org/C111472728","wikidata":"https://www.wikidata.org/wiki/Q9471","display_name":"Epistemology","level":1,"score":0.0}],"mesh":[],"locations_count":8,"locations":[{"id":"doi:10.1007/s00224-020-10002-z","is_oa":true,"landing_page_url":"https://doi.org/10.1007/s00224-020-10002-z","pdf_url":"https://link.springer.com/content/pdf/10.1007/s00224-020-10002-z.pdf","source":{"id":"https://openalex.org/S4210177266","display_name":"Theory of Computing Systems","issn_l":"1432-4350","issn":["1432-4350","1433-0490"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310319900","host_organization_name":"Springer Science+Business Media","host_organization_lineage":["https://openalex.org/P4310319900","https://openalex.org/P4310319965"],"host_organization_lineage_names":["Springer Science+Business Media","Springer Nature"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Theory of Computing Systems","raw_type":"journal-article"},{"id":"pmid:33568963","is_oa":false,"landing_page_url":"https://pubmed.ncbi.nlm.nih.gov/33568963","pdf_url":null,"source":{"id":"https://openalex.org/S4306525036","display_name":"PubMed","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I1299303238","host_organization_name":"National Institutes of Health","host_organization_lineage":["https://openalex.org/I1299303238"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Theory of computing systems","raw_type":null},{"id":"pmh:oai:HAL:hal-02351463v1","is_oa":false,"landing_page_url":"https://hal.science/hal-02351463","pdf_url":null,"source":{"id":"https://openalex.org/S4306402512","display_name":"HAL (Le Centre pour la Communication Scientifique Directe)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I1294671590","host_organization_name":"Centre National de la Recherche Scientifique","host_organization_lineage":["https://openalex.org/I1294671590"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"International Conference on Database Theory, Mar 2019, Lisbon, Portugal","raw_type":"info:eu-repo/semantics/conferenceObject"},{"id":"pmh:oai:HAL:hal-03402343v1","is_oa":false,"landing_page_url":"https://hal.science/hal-03402343","pdf_url":null,"source":{"id":"https://openalex.org/S4306402512","display_name":"HAL (Le Centre pour la Communication Scientifique Directe)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I1294671590","host_organization_name":"Centre National de la Recherche Scientifique","host_organization_lineage":["https://openalex.org/I1294671590"],"host_organization_lineage_names":[],"type":"repository"},"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"Theory of Computing Systems, 2021, 65 (1), pp.3-41. &#x27E8;10.1007/s00224-020-10002-z&#x27E9;","raw_type":"info:eu-repo/semantics/article"},{"id":"pmh:oai:drops-oai.dagstuhl.de:10322","is_oa":true,"landing_page_url":"https://drops.dagstuhl.de/entities/document/10.4230/LIPIcs.ICDT.2019.20","pdf_url":null,"source":{"id":"https://openalex.org/S4377196569","display_name":"DROPS (Schloss Dagstuhl \u2013 Leibniz Center for Informatics)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I2799853480","host_organization_name":"Schloss Dagstuhl \u2013 Leibniz Center for Informatics","host_organization_lineage":["https://openalex.org/I2799853480"],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"","raw_type":"InProceedings"},{"id":"pmh:oai:europepmc.org:6773670","is_oa":true,"landing_page_url":"http://europepmc.org/pmc/articles/PMC7853710","pdf_url":null,"source":{"id":"https://openalex.org/S4306400806","display_name":"Europe PMC (PubMed Central)","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I1303153112","host_organization_name":"European Bioinformatics Institute","host_organization_lineage":["https://openalex.org/I1303153112"],"host_organization_lineage_names":[],"type":"repository"},"license":"other-oa","license_id":"https://openalex.org/licenses/other-oa","version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"","raw_type":"Text"},{"id":"pmh:oai:pubmedcentral.nih.gov:7853710","is_oa":true,"landing_page_url":"https://www.ncbi.nlm.nih.gov/pmc/articles/7853710","pdf_url":null,"source":{"id":"https://openalex.org/S2764455111","display_name":"PubMed Central","issn_l":null,"issn":null,"is_oa":true,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/I1299303238","host_organization_name":"National Institutes of Health","host_organization_lineage":["https://openalex.org/I1299303238"],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"Theory Comput Syst","raw_type":"Text"},{"id":"doi:10.4230/lipics.icdt.2019.20","is_oa":true,"landing_page_url":"https://doi.org/10.4230/lipics.icdt.2019.20","pdf_url":null,"source":{"id":"https://openalex.org/S7407052059","display_name":"Dagstuhl Research Online Publication Server","issn_l":null,"issn":null,"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":null,"host_organization_name":null,"host_organization_lineage":[],"host_organization_lineage_names":[],"type":"repository"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":null,"is_accepted":false,"is_published":null,"raw_source_name":null,"raw_type":"ConferencePaper"}],"best_oa_location":{"id":"doi:10.1007/s00224-020-10002-z","is_oa":true,"landing_page_url":"https://doi.org/10.1007/s00224-020-10002-z","pdf_url":"https://link.springer.com/content/pdf/10.1007/s00224-020-10002-z.pdf","source":{"id":"https://openalex.org/S4210177266","display_name":"Theory of Computing Systems","issn_l":"1432-4350","issn":["1432-4350","1433-0490"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310319900","host_organization_name":"Springer Science+Business Media","host_organization_lineage":["https://openalex.org/P4310319900","https://openalex.org/P4310319965"],"host_organization_lineage_names":["Springer Science+Business Media","Springer Nature"],"type":"journal"},"license":"cc-by","license_id":"https://openalex.org/licenses/cc-by","version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Theory of Computing Systems","raw_type":"journal-article"},"sustainable_development_goals":[{"score":0.6600000262260437,"id":"https://metadata.un.org/sdg/4","display_name":"Quality Education"}],"awards":[{"id":"https://openalex.org/G3867201627","display_name":"HyperTrac:hypergraph Decompositions and Tractability","funder_award_id":"P30930","funder_id":"https://openalex.org/F4320321181","funder_display_name":"Austrian Science Fund"},{"id":"https://openalex.org/G6631213480","display_name":null,"funder_award_id":"P30930-N35","funder_id":"https://openalex.org/F4320321181","funder_display_name":"Austrian Science Fund"}],"funders":[{"id":"https://openalex.org/F4320321181","display_name":"Austrian Science Fund","ror":"https://ror.org/013tf3c58"}],"has_content":{"pdf":true,"grobid_xml":true},"content_urls":{"pdf":"https://content.openalex.org/works/W2908453256.pdf","grobid_xml":"https://content.openalex.org/works/W2908453256.grobid-xml"},"referenced_works_count":19,"referenced_works":["https://openalex.org/W63340727","https://openalex.org/W1565047086","https://openalex.org/W1988714410","https://openalex.org/W1989038407","https://openalex.org/W1998342956","https://openalex.org/W2025038593","https://openalex.org/W2027519504","https://openalex.org/W2027702526","https://openalex.org/W2033267049","https://openalex.org/W2039914844","https://openalex.org/W2048685245","https://openalex.org/W2088101961","https://openalex.org/W2111829945","https://openalex.org/W2131785201","https://openalex.org/W2159738186","https://openalex.org/W2171984098","https://openalex.org/W2338508724","https://openalex.org/W2888755732","https://openalex.org/W2962826847"],"related_works":["https://openalex.org/W4248389398","https://openalex.org/W4238075012","https://openalex.org/W4239346220","https://openalex.org/W2746162205","https://openalex.org/W4251993441","https://openalex.org/W2365154038","https://openalex.org/W2386767533","https://openalex.org/W2570335447","https://openalex.org/W2351009956","https://openalex.org/W4225259759"],"abstract_inverted_index":{"We":[0,83,168],"study":[1],"the":[2,16,22,55,116,129,144,149,155,171,174],"complexity":[3,107],"of":[4,21,29,54,57,74,93,97,118,128,132,148],"evaluating":[5],"well-designed":[6,58,99,111,119],"pattern":[7,59,100,112,153,160],"trees,":[8],"a":[9,51,91,125],"query":[10,23,76],"language":[11],"extending":[12],"conjunctive":[13],"queries":[14,122,133],"with":[15,102,134],"possibility":[17,28],"to":[18,24,115,179],"define":[19],"parts":[20,31],"be":[25,63,141],"optional.":[26],"This":[27],"optional":[30],"is":[32,44],"important":[33],"for":[34,158,173],"obtaining":[35],"meaningful":[36],"results":[37],"over":[38],"incomplete":[39],"data":[40],"sources":[41],"as":[42],"it":[43],"common":[45,106],"in":[46,65,80,136,177],"semantic":[47],"web":[48],"settings.":[49],"Recently,":[50],"structural":[52],"characterization":[53,92,172],"classes":[56,96,131],"trees":[60,101,113,154,161],"that":[61,139],"can":[62,140],"evaluated":[64],"polynomial":[66],"time":[67],"was":[68],"shown.":[69],"However,":[70],"projection-a":[71],"central":[72],"feature":[73],"many":[75],"languages-was":[77],"not":[78,163],"considered":[79],"this":[81,87,123,137],"study.":[82],"work":[84],"towards":[85],"closing":[86],"gap":[88],"by":[89,143],"giving":[90],"all":[94,165],"tractable":[95,130,166,183],"simple":[98,159],"projection":[103],"(under":[104],"some":[105,181],"theoretic":[108],"assumptions).":[109],"Since":[110],"correspond":[114],"fragment":[117,138],"{AND,":[120],"OPTIONAL}-SPARQL":[121],"gives":[124],"complete":[126],"description":[127],"projections":[135],"characterized":[142],"underlying":[145],"graph":[146],"structures":[147],"queries.":[150],"For":[151],"non-simple":[152,175],"tractability":[156],"criteria":[157],"do":[162],"capture":[164,180],"classes.":[167],"thus":[169],"extend":[170],"case":[176],"order":[178],"additional":[182],"cases.":[184]},"counts_by_year":[],"updated_date":"2026-07-23T08:03:31.855105","created_date":"2025-10-10T00:00:00"}
