{"id":"https://openalex.org/W2061378086","doi":"https://doi.org/10.1016/s0020-0190(97)00111-7","title":"A characterization of the leaf language classes","display_name":"A characterization of the leaf language classes","publication_year":1997,"publication_date":"1997-08-01","ids":{"openalex":"https://openalex.org/W2061378086","doi":"https://doi.org/10.1016/s0020-0190(97)00111-7","mag":"2061378086"},"language":"en","primary_location":{"id":"doi:10.1016/s0020-0190(97)00111-7","is_oa":false,"landing_page_url":"https://doi.org/10.1016/s0020-0190(97)00111-7","pdf_url":null,"source":{"id":"https://openalex.org/S147953040","display_name":"Information Processing Letters","issn_l":"0020-0190","issn":["0020-0190","1872-6119"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310320990","host_organization_name":"Elsevier BV","host_organization_lineage":["https://openalex.org/P4310320990"],"host_organization_lineage_names":["Elsevier BV"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Information Processing Letters","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/A5110628039","display_name":"Bernd Borchert","orcid":null},"institutions":[{"id":"https://openalex.org/I4210147766","display_name":"Gerresheimer (Germany)","ror":"https://ror.org/055txj157","country_code":"DE","type":"company","lineage":["https://openalex.org/I4210147766"]}],"countries":["DE"],"is_corresponding":false,"raw_author_name":"Bernd Borchert","raw_affiliation_strings":["Im Neuenheimer Feld 294, 69120 Heidelberg, Germany"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Im Neuenheimer Feld 294, 69120 Heidelberg, Germany","institution_ids":["https://openalex.org/I4210147766"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5056847255","display_name":"Riccardo Silvestri","orcid":null},"institutions":[{"id":"https://openalex.org/I4210101866","display_name":"Informa (Italy)","ror":"https://ror.org/017c2y429","country_code":"IT","type":"company","lineage":["https://openalex.org/I4210101866","https://openalex.org/I4210154378"]},{"id":"https://openalex.org/I861853513","display_name":"Sapienza University of Rome","ror":"https://ror.org/02be6w209","country_code":"IT","type":"education","lineage":["https://openalex.org/I861853513"]}],"countries":["IT"],"is_corresponding":true,"raw_author_name":"Riccardo Silvestri","raw_affiliation_strings":["Dipartimento di Scienze dell'Informazione, Universit\u00e0 di Roma \u201cLa Sapienza\u201d, Via Salaria 113, I-00198 Roma, Italy","Dipartimento di Scienze dell'Informazione - Universit\u00e0 di Roma \u2018La Sapienza\u2019 - Via Salaria, 113 - I-00198, Roma, Italy"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Dipartimento di Scienze dell'Informazione, Universit\u00e0 di Roma \u201cLa Sapienza\u201d, Via Salaria 113, I-00198 Roma, Italy","institution_ids":["https://openalex.org/I4210101866","https://openalex.org/I861853513"]},{"raw_affiliation_string":"Dipartimento di Scienze dell'Informazione - Universit\u00e0 di Roma \u2018La Sapienza\u2019 - Via Salaria, 113 - I-00198, Roma, Italy","institution_ids":["https://openalex.org/I861853513"]}]}],"institutions":[],"countries_distinct_count":2,"institutions_distinct_count":3,"corresponding_author_ids":["https://openalex.org/A5056847255"],"corresponding_institution_ids":["https://openalex.org/I4210101866","https://openalex.org/I861853513"],"apc_list":{"value":2040,"currency":"USD","value_usd":2040},"apc_paid":null,"fwci":0.5096,"has_fulltext":false,"cited_by_count":8,"citation_normalized_percentile":{"value":0.65797249,"is_in_top_1_percent":false,"is_in_top_10_percent":false},"cited_by_percentile_year":{"min":89,"max":94},"biblio":{"volume":"63","issue":"3","first_page":"153","last_page":"158"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T11567","display_name":"semigroups and automata theory","score":0.9997000098228455,"subfield":{"id":"https://openalex.org/subfields/1703","display_name":"Computational Theory and Mathematics"},"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/T11567","display_name":"semigroups and automata theory","score":0.9997000098228455,"subfield":{"id":"https://openalex.org/subfields/1703","display_name":"Computational Theory and Mathematics"},"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/T10374","display_name":"Advanced Graph Theory Research","score":0.9977999925613403,"subfield":{"id":"https://openalex.org/subfields/1703","display_name":"Computational Theory and Mathematics"},"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/T10142","display_name":"Formal Methods in Verification","score":0.996999979019165,"subfield":{"id":"https://openalex.org/subfields/1703","display_name":"Computational Theory and Mathematics"},"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/countable-set","display_name":"Countable set","score":0.797269344329834},{"id":"https://openalex.org/keywords/disjoint-sets","display_name":"Disjoint sets","score":0.7138404846191406},{"id":"https://openalex.org/keywords/set","display_name":"Set (abstract data type)","score":0.670339822769165},{"id":"https://openalex.org/keywords/mathematics","display_name":"Mathematics","score":0.6404691934585571},{"id":"https://openalex.org/keywords/characterization","display_name":"Characterization (materials science)","score":0.6315947771072388},{"id":"https://openalex.org/keywords/time-complexity","display_name":"Time complexity","score":0.5122377276420593},{"id":"https://openalex.org/keywords/combinatorics","display_name":"Combinatorics","score":0.5080749988555908},{"id":"https://openalex.org/keywords/discrete-mathematics","display_name":"Discrete mathematics","score":0.4987366199493408},{"id":"https://openalex.org/keywords/regular-language","display_name":"Regular language","score":0.4895840585231781},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.3027597665786743},{"id":"https://openalex.org/keywords/theoretical-computer-science","display_name":"Theoretical computer science","score":0.20568060874938965},{"id":"https://openalex.org/keywords/programming-language","display_name":"Programming language","score":0.12047022581100464},{"id":"https://openalex.org/keywords/automaton","display_name":"Automaton","score":0.06475722789764404}],"concepts":[{"id":"https://openalex.org/C110729354","wikidata":"https://www.wikidata.org/wiki/Q185478","display_name":"Countable set","level":2,"score":0.797269344329834},{"id":"https://openalex.org/C45340560","wikidata":"https://www.wikidata.org/wiki/Q215382","display_name":"Disjoint sets","level":2,"score":0.7138404846191406},{"id":"https://openalex.org/C177264268","wikidata":"https://www.wikidata.org/wiki/Q1514741","display_name":"Set (abstract data type)","level":2,"score":0.670339822769165},{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.6404691934585571},{"id":"https://openalex.org/C2780841128","wikidata":"https://www.wikidata.org/wiki/Q5073781","display_name":"Characterization (materials science)","level":2,"score":0.6315947771072388},{"id":"https://openalex.org/C311688","wikidata":"https://www.wikidata.org/wiki/Q2393193","display_name":"Time complexity","level":2,"score":0.5122377276420593},{"id":"https://openalex.org/C114614502","wikidata":"https://www.wikidata.org/wiki/Q76592","display_name":"Combinatorics","level":1,"score":0.5080749988555908},{"id":"https://openalex.org/C118615104","wikidata":"https://www.wikidata.org/wiki/Q121416","display_name":"Discrete mathematics","level":1,"score":0.4987366199493408},{"id":"https://openalex.org/C52370388","wikidata":"https://www.wikidata.org/wiki/Q752532","display_name":"Regular language","level":3,"score":0.4895840585231781},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.3027597665786743},{"id":"https://openalex.org/C80444323","wikidata":"https://www.wikidata.org/wiki/Q2878974","display_name":"Theoretical computer science","level":1,"score":0.20568060874938965},{"id":"https://openalex.org/C199360897","wikidata":"https://www.wikidata.org/wiki/Q9143","display_name":"Programming language","level":1,"score":0.12047022581100464},{"id":"https://openalex.org/C112505250","wikidata":"https://www.wikidata.org/wiki/Q787116","display_name":"Automaton","level":2,"score":0.06475722789764404},{"id":"https://openalex.org/C192562407","wikidata":"https://www.wikidata.org/wiki/Q228736","display_name":"Materials science","level":0,"score":0.0},{"id":"https://openalex.org/C171250308","wikidata":"https://www.wikidata.org/wiki/Q11468","display_name":"Nanotechnology","level":1,"score":0.0}],"mesh":[],"locations_count":2,"locations":[{"id":"doi:10.1016/s0020-0190(97)00111-7","is_oa":false,"landing_page_url":"https://doi.org/10.1016/s0020-0190(97)00111-7","pdf_url":null,"source":{"id":"https://openalex.org/S147953040","display_name":"Information Processing Letters","issn_l":"0020-0190","issn":["0020-0190","1872-6119"],"is_oa":false,"is_in_doaj":false,"is_core":true,"host_organization":"https://openalex.org/P4310320990","host_organization_name":"Elsevier BV","host_organization_lineage":["https://openalex.org/P4310320990"],"host_organization_lineage_names":["Elsevier BV"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Information Processing Letters","raw_type":"journal-article"},{"id":"pmh:oai:CiteSeerX.psu:10.1.1.56.4225","is_oa":false,"landing_page_url":"http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.56.4225","pdf_url":null,"source":null,"license":null,"license_id":null,"version":"submittedVersion","is_accepted":false,"is_published":false,"raw_source_name":"http://math.uni-heidelberg.de/logic/bb/papers/leaf-languages.ps","raw_type":"text"}],"best_oa_location":null,"sustainable_development_goals":[{"display_name":"Quality Education","score":0.5799999833106995,"id":"https://metadata.un.org/sdg/4"}],"awards":[],"funders":[],"has_content":{"grobid_xml":false,"pdf":false},"content_urls":null,"referenced_works_count":30,"referenced_works":["https://openalex.org/W156977962","https://openalex.org/W1486265152","https://openalex.org/W1511738550","https://openalex.org/W1569394207","https://openalex.org/W1580758408","https://openalex.org/W1816633894","https://openalex.org/W1946987616","https://openalex.org/W1970624740","https://openalex.org/W1975790950","https://openalex.org/W1985034344","https://openalex.org/W1993576444","https://openalex.org/W2048383625","https://openalex.org/W2052936500","https://openalex.org/W2061489447","https://openalex.org/W2065826812","https://openalex.org/W2069919161","https://openalex.org/W2100570449","https://openalex.org/W2160722924","https://openalex.org/W3127823229","https://openalex.org/W4213009134","https://openalex.org/W4243643814","https://openalex.org/W6606407729","https://openalex.org/W6629043965","https://openalex.org/W6634141081","https://openalex.org/W6634375940","https://openalex.org/W6638284403","https://openalex.org/W6648698145","https://openalex.org/W6667944808","https://openalex.org/W6683732762","https://openalex.org/W6884721023"],"related_works":["https://openalex.org/W4256429076","https://openalex.org/W1971174658","https://openalex.org/W3107994849","https://openalex.org/W2099195351","https://openalex.org/W1631776469","https://openalex.org/W2950866767","https://openalex.org/W26693340","https://openalex.org/W2088461731","https://openalex.org/W2964091527","https://openalex.org/W1560765090"],"abstract_inverted_index":null,"counts_by_year":[{"year":2013,"cited_by_count":1}],"updated_date":"2026-07-23T08:03:31.855105","created_date":"2025-10-10T00:00:00"}