{"id":"https://openalex.org/W2077039808","doi":"https://doi.org/10.1016/s0019-9958(84)80013-3","title":"An easy proof of Greibach normal form","display_name":"An easy proof of Greibach normal form","publication_year":1984,"publication_date":"1984-12-01","ids":{"openalex":"https://openalex.org/W2077039808","doi":"https://doi.org/10.1016/s0019-9958(84)80013-3","mag":"2077039808"},"language":"en","primary_location":{"id":"doi:10.1016/s0019-9958(84)80013-3","is_oa":true,"landing_page_url":"https://doi.org/10.1016/s0019-9958(84)80013-3","pdf_url":"https://www.sciencedirect.com/science/article/pii/S0019995884800133/pdf","source":{"id":"https://openalex.org/S4210192454","display_name":"Information and Control","issn_l":"0019-9958","issn":["0019-9958","1878-2981"],"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/P4310319955","host_organization_name":"Academic Press","host_organization_lineage":["https://openalex.org/P4310319955","https://openalex.org/P4310320990"],"host_organization_lineage_names":["Academic Press","Elsevier BV"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Information and Control","raw_type":"journal-article"},"type":"article","indexed_in":["crossref"],"open_access":{"is_oa":true,"oa_status":"bronze","oa_url":"https://www.sciencedirect.com/science/article/pii/S0019995884800133/pdf","any_repository_has_fulltext":false},"authorships":[{"author_position":"first","author":{"id":"https://openalex.org/A5045244980","display_name":"Andrzej Ehrenfeucht","orcid":null},"institutions":[{"id":"https://openalex.org/I188538660","display_name":"University of Colorado Boulder","ror":"https://ror.org/02ttsq026","country_code":"US","type":"education","lineage":["https://openalex.org/I188538660"]}],"countries":["US"],"is_corresponding":false,"raw_author_name":"Andrzej Ehrenfeucht","raw_affiliation_strings":["University of Colorado, Department of Computer Science, Boulder, Colorado 80309 USA"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"University of Colorado, Department of Computer Science, Boulder, Colorado 80309 USA","institution_ids":["https://openalex.org/I188538660"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5110486000","display_name":"Grzegorz Rozenberg","orcid":null},"institutions":[{"id":"https://openalex.org/I121797337","display_name":"Leiden University","ror":"https://ror.org/027bh9e22","country_code":"NL","type":"education","lineage":["https://openalex.org/I121797337"]},{"id":"https://openalex.org/I210716285","display_name":"University of Applied Sciences Leiden","ror":"https://ror.org/0093src13","country_code":"NL","type":"education","lineage":["https://openalex.org/I210716285"]}],"countries":["NL"],"is_corresponding":true,"raw_author_name":"Grzegorz Rozenberg","raw_affiliation_strings":["Institute of Applied Mathematics and Computer Science, University of Leiden, Leiden, The Netherlands","Institute of Applied Mathematics and Computer Science, University of Leiden, Leiden The Netherlands"],"raw_orcid":null,"affiliations":[{"raw_affiliation_string":"Institute of Applied Mathematics and Computer Science, University of Leiden, Leiden, The Netherlands","institution_ids":["https://openalex.org/I210716285"]},{"raw_affiliation_string":"Institute of Applied Mathematics and Computer Science, University of Leiden, Leiden The Netherlands","institution_ids":["https://openalex.org/I121797337"]}]}],"institutions":[],"countries_distinct_count":2,"institutions_distinct_count":3,"corresponding_author_ids":["https://openalex.org/A5110486000"],"corresponding_institution_ids":["https://openalex.org/I121797337","https://openalex.org/I210716285"],"apc_list":null,"apc_paid":null,"fwci":0.5195,"has_fulltext":true,"cited_by_count":9,"citation_normalized_percentile":{"value":0.66081751,"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":"190","last_page":"199"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T11567","display_name":"semigroups and automata theory","score":0.9988999962806702,"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":0.9988999962806702,"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/T11269","display_name":"Algorithms and Data Compression","score":0.9961000084877014,"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/T10948","display_name":"Advanced Combinatorial Mathematics","score":0.991100013256073,"subfield":{"id":"https://openalex.org/subfields/2607","display_name":"Discrete Mathematics and Combinatorics"},"field":{"id":"https://openalex.org/fields/26","display_name":"Mathematics"},"domain":{"id":"https://openalex.org/domains/3","display_name":"Physical Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/context-free-grammar","display_name":"Context-free grammar","score":0.7812499403953552},{"id":"https://openalex.org/keywords/grammar","display_name":"Grammar","score":0.6173941493034363},{"id":"https://openalex.org/keywords/tree-adjoining-grammar","display_name":"Tree-adjoining grammar","score":0.5871453285217285},{"id":"https://openalex.org/keywords/mildly-context-sensitive-grammar-formalism","display_name":"Mildly context-sensitive grammar formalism","score":0.5702149271965027},{"id":"https://openalex.org/keywords/rule-based-machine-translation","display_name":"Rule-based machine translation","score":0.5674263834953308},{"id":"https://openalex.org/keywords/computer-science","display_name":"Computer science","score":0.5333454608917236},{"id":"https://openalex.org/keywords/context","display_name":"Context (archaeology)","score":0.5298221707344055},{"id":"https://openalex.org/keywords/context-sensitive-grammar","display_name":"Context-sensitive grammar","score":0.5126072764396667},{"id":"https://openalex.org/keywords/upper-and-lower-bounds","display_name":"Upper and lower bounds","score":0.4973199665546417},{"id":"https://openalex.org/keywords/mathematics","display_name":"Mathematics","score":0.4487912058830261},{"id":"https://openalex.org/keywords/generative-grammar","display_name":"Generative grammar","score":0.28093570470809937},{"id":"https://openalex.org/keywords/phrase-structure-rules","display_name":"Phrase structure rules","score":0.2211633324623108},{"id":"https://openalex.org/keywords/natural-language-processing","display_name":"Natural language processing","score":0.18967819213867188},{"id":"https://openalex.org/keywords/artificial-intelligence","display_name":"Artificial intelligence","score":0.1705174446105957},{"id":"https://openalex.org/keywords/linguistics","display_name":"Linguistics","score":0.15555179119110107}],"concepts":[{"id":"https://openalex.org/C97212296","wikidata":"https://www.wikidata.org/wiki/Q338047","display_name":"Context-free grammar","level":3,"score":0.7812499403953552},{"id":"https://openalex.org/C26022165","wikidata":"https://www.wikidata.org/wiki/Q8091","display_name":"Grammar","level":2,"score":0.6173941493034363},{"id":"https://openalex.org/C134083981","wikidata":"https://www.wikidata.org/wiki/Q1754022","display_name":"Tree-adjoining grammar","level":4,"score":0.5871453285217285},{"id":"https://openalex.org/C172265290","wikidata":"https://www.wikidata.org/wiki/Q6134957","display_name":"Mildly context-sensitive grammar formalism","level":4,"score":0.5702149271965027},{"id":"https://openalex.org/C53893814","wikidata":"https://www.wikidata.org/wiki/Q7378909","display_name":"Rule-based machine translation","level":2,"score":0.5674263834953308},{"id":"https://openalex.org/C41008148","wikidata":"https://www.wikidata.org/wiki/Q21198","display_name":"Computer science","level":0,"score":0.5333454608917236},{"id":"https://openalex.org/C2779343474","wikidata":"https://www.wikidata.org/wiki/Q3109175","display_name":"Context (archaeology)","level":2,"score":0.5298221707344055},{"id":"https://openalex.org/C125950753","wikidata":"https://www.wikidata.org/wiki/Q908674","display_name":"Context-sensitive grammar","level":4,"score":0.5126072764396667},{"id":"https://openalex.org/C77553402","wikidata":"https://www.wikidata.org/wiki/Q13222579","display_name":"Upper and lower bounds","level":2,"score":0.4973199665546417},{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.4487912058830261},{"id":"https://openalex.org/C39890363","wikidata":"https://www.wikidata.org/wiki/Q36108","display_name":"Generative grammar","level":2,"score":0.28093570470809937},{"id":"https://openalex.org/C80877019","wikidata":"https://www.wikidata.org/wiki/Q7188074","display_name":"Phrase structure rules","level":3,"score":0.2211633324623108},{"id":"https://openalex.org/C204321447","wikidata":"https://www.wikidata.org/wiki/Q30642","display_name":"Natural language processing","level":1,"score":0.18967819213867188},{"id":"https://openalex.org/C154945302","wikidata":"https://www.wikidata.org/wiki/Q11660","display_name":"Artificial intelligence","level":1,"score":0.1705174446105957},{"id":"https://openalex.org/C41895202","wikidata":"https://www.wikidata.org/wiki/Q8162","display_name":"Linguistics","level":1,"score":0.15555179119110107},{"id":"https://openalex.org/C86803240","wikidata":"https://www.wikidata.org/wiki/Q420","display_name":"Biology","level":0,"score":0.0},{"id":"https://openalex.org/C138885662","wikidata":"https://www.wikidata.org/wiki/Q5891","display_name":"Philosophy","level":0,"score":0.0},{"id":"https://openalex.org/C151730666","wikidata":"https://www.wikidata.org/wiki/Q7205","display_name":"Paleontology","level":1,"score":0.0},{"id":"https://openalex.org/C134306372","wikidata":"https://www.wikidata.org/wiki/Q7754","display_name":"Mathematical analysis","level":1,"score":0.0}],"mesh":[],"locations_count":1,"locations":[{"id":"doi:10.1016/s0019-9958(84)80013-3","is_oa":true,"landing_page_url":"https://doi.org/10.1016/s0019-9958(84)80013-3","pdf_url":"https://www.sciencedirect.com/science/article/pii/S0019995884800133/pdf","source":{"id":"https://openalex.org/S4210192454","display_name":"Information and Control","issn_l":"0019-9958","issn":["0019-9958","1878-2981"],"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/P4310319955","host_organization_name":"Academic Press","host_organization_lineage":["https://openalex.org/P4310319955","https://openalex.org/P4310320990"],"host_organization_lineage_names":["Academic Press","Elsevier BV"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Information and Control","raw_type":"journal-article"}],"best_oa_location":{"id":"doi:10.1016/s0019-9958(84)80013-3","is_oa":true,"landing_page_url":"https://doi.org/10.1016/s0019-9958(84)80013-3","pdf_url":"https://www.sciencedirect.com/science/article/pii/S0019995884800133/pdf","source":{"id":"https://openalex.org/S4210192454","display_name":"Information and Control","issn_l":"0019-9958","issn":["0019-9958","1878-2981"],"is_oa":false,"is_in_doaj":false,"is_core":false,"host_organization":"https://openalex.org/P4310319955","host_organization_name":"Academic Press","host_organization_lineage":["https://openalex.org/P4310319955","https://openalex.org/P4310320990"],"host_organization_lineage_names":["Academic Press","Elsevier BV"],"type":"journal"},"license":null,"license_id":null,"version":"publishedVersion","is_accepted":true,"is_published":true,"raw_source_name":"Information and Control","raw_type":"journal-article"},"sustainable_development_goals":[{"display_name":"Quality Education","score":0.75,"id":"https://metadata.un.org/sdg/4"}],"awards":[],"funders":[{"id":"https://openalex.org/F4320306076","display_name":"National Science Foundation","ror":"https://ror.org/021nxhr62"}],"has_content":{"grobid_xml":true,"pdf":true},"content_urls":{"pdf":"https://content.openalex.org/works/W2077039808.pdf","grobid_xml":"https://content.openalex.org/works/W2077039808.grobid-xml"},"referenced_works_count":4,"referenced_works":["https://openalex.org/W956032893","https://openalex.org/W1535681052","https://openalex.org/W2054160268","https://openalex.org/W2914032487"],"related_works":["https://openalex.org/W59084530","https://openalex.org/W1557335907","https://openalex.org/W1586408085","https://openalex.org/W1656514314","https://openalex.org/W1991706120","https://openalex.org/W3009523905","https://openalex.org/W2055334547","https://openalex.org/W281298494","https://openalex.org/W2035755645","https://openalex.org/W2132458243"],"abstract_inverted_index":null,"counts_by_year":[{"year":2014,"cited_by_count":1}],"updated_date":"2026-07-31T08:31:51.225901","created_date":"2025-10-10T00:00:00"}
