{"id":"https://openalex.org/W2054308287","doi":"https://doi.org/10.1016/0166-218x(81)90006-8","title":"Decidability and density in two-symbol grammar forms","display_name":"Decidability and density in two-symbol grammar forms","publication_year":1981,"publication_date":"1981-11-01","ids":{"openalex":"https://openalex.org/W2054308287","doi":"https://doi.org/10.1016/0166-218x(81)90006-8","mag":"2054308287"},"language":"en","primary_location":{"id":"doi:10.1016/0166-218x(81)90006-8","is_oa":false,"landing_page_url":"https://doi.org/10.1016/0166-218x(81)90006-8","pdf_url":null,"source":{"id":"https://openalex.org/S171741597","display_name":"Discrete Applied Mathematics","issn_l":"0166-218X","issn":["0166-218X","1872-6771"],"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":"Discrete Applied 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/A5026864542","display_name":"Hermann Maurer","orcid":null},"institutions":[{"id":"https://openalex.org/I4092182","display_name":"Graz University of Technology","ror":"https://ror.org/00d7xrm67","country_code":"AT","type":"education","lineage":["https://openalex.org/I4092182"]}],"countries":["AT"],"is_corresponding":true,"raw_author_name":"H.A. Maurer","raw_affiliation_strings":["Institut f\u00fcr Informationsverarbeitung, Technische Universit\u00e4t Graz, A-8010 Graz, Austria"],"affiliations":[{"raw_affiliation_string":"Institut f\u00fcr Informationsverarbeitung, Technische Universit\u00e4t Graz, A-8010 Graz, Austria","institution_ids":["https://openalex.org/I4092182"]}]},{"author_position":"middle","author":{"id":"https://openalex.org/A5113478603","display_name":"A. Salomaa","orcid":null},"institutions":[{"id":"https://openalex.org/I155660961","display_name":"University of Turku","ror":"https://ror.org/05vghhr25","country_code":"FI","type":"education","lineage":["https://openalex.org/I155660961"]}],"countries":["FI"],"is_corresponding":false,"raw_author_name":"A. Salomaa","raw_affiliation_strings":["Department of Mathematics, University of Turku, SF-20500 Turku 50, Finland#TAB#"],"affiliations":[{"raw_affiliation_string":"Department of Mathematics, University of Turku, SF-20500 Turku 50, Finland#TAB#","institution_ids":["https://openalex.org/I155660961"]}]},{"author_position":"last","author":{"id":"https://openalex.org/A5110482098","display_name":"D. Wood","orcid":null},"institutions":[{"id":"https://openalex.org/I98251732","display_name":"McMaster University","ror":"https://ror.org/02fa3aq29","country_code":"CA","type":"education","lineage":["https://openalex.org/I98251732"]}],"countries":["CA"],"is_corresponding":false,"raw_author_name":"D. Wood","raw_affiliation_strings":["Unit for Computer Science, McMaster University, Hamilton, Ontario, Canada, L8S 4K1#TAB#"],"affiliations":[{"raw_affiliation_string":"Unit for Computer Science, McMaster University, Hamilton, Ontario, Canada, L8S 4K1#TAB#","institution_ids":["https://openalex.org/I98251732"]}]}],"institutions":[],"countries_distinct_count":3,"institutions_distinct_count":3,"corresponding_author_ids":["https://openalex.org/A5026864542"],"corresponding_institution_ids":["https://openalex.org/I4092182"],"apc_list":{"value":2750,"currency":"USD","value_usd":2750},"apc_paid":null,"fwci":3.47,"has_fulltext":false,"cited_by_count":10,"citation_normalized_percentile":{"value":0.93115172,"is_in_top_1_percent":false,"is_in_top_10_percent":true},"cited_by_percentile_year":null,"biblio":{"volume":"3","issue":"4","first_page":"289","last_page":"299"},"is_retracted":false,"is_paratext":false,"is_xpac":false,"primary_topic":{"id":"https://openalex.org/T11567","display_name":"semigroups and automata theory","score":0.9998999834060669,"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":0.9998999834060669,"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/T10181","display_name":"Natural Language Processing Techniques","score":0.9988999962806702,"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/T12029","display_name":"DNA and Biological Computing","score":0.9847000241279602,"subfield":{"id":"https://openalex.org/subfields/1312","display_name":"Molecular Biology"},"field":{"id":"https://openalex.org/fields/13","display_name":"Biochemistry, Genetics and Molecular Biology"},"domain":{"id":"https://openalex.org/domains/1","display_name":"Life Sciences"}}],"keywords":[{"id":"https://openalex.org/keywords/terminal-and-nonterminal-symbols","display_name":"Terminal and nonterminal symbols","score":0.9512543082237244},{"id":"https://openalex.org/keywords/mathematics","display_name":"Mathematics","score":0.8382893800735474},{"id":"https://openalex.org/keywords/symbol","display_name":"Symbol (formal)","score":0.7577102184295654},{"id":"https://openalex.org/keywords/decidability","display_name":"Decidability","score":0.7173935174942017},{"id":"https://openalex.org/keywords/equivalence","display_name":"Equivalence (formal languages)","score":0.6640779376029968},{"id":"https://openalex.org/keywords/grammar","display_name":"Grammar","score":0.5881001949310303},{"id":"https://openalex.org/keywords/combinatorics","display_name":"Combinatorics","score":0.53816819190979},{"id":"https://openalex.org/keywords/context-free-grammar","display_name":"Context-free grammar","score":0.4291123151779175},{"id":"https://openalex.org/keywords/context","display_name":"Context (archaeology)","score":0.4263985753059387},{"id":"https://openalex.org/keywords/discrete-mathematics","display_name":"Discrete mathematics","score":0.36764025688171387},{"id":"https://openalex.org/keywords/linguistics","display_name":"Linguistics","score":0.23180881142616272}],"concepts":[{"id":"https://openalex.org/C9432014","wikidata":"https://www.wikidata.org/wiki/Q954063","display_name":"Terminal and nonterminal symbols","level":3,"score":0.9512543082237244},{"id":"https://openalex.org/C33923547","wikidata":"https://www.wikidata.org/wiki/Q395","display_name":"Mathematics","level":0,"score":0.8382893800735474},{"id":"https://openalex.org/C134400042","wikidata":"https://www.wikidata.org/wiki/Q2372244","display_name":"Symbol (formal)","level":2,"score":0.7577102184295654},{"id":"https://openalex.org/C153269930","wikidata":"https://www.wikidata.org/wiki/Q430001","display_name":"Decidability","level":2,"score":0.7173935174942017},{"id":"https://openalex.org/C2780069185","wikidata":"https://www.wikidata.org/wiki/Q7977945","display_name":"Equivalence (formal languages)","level":2,"score":0.6640779376029968},{"id":"https://openalex.org/C26022165","wikidata":"https://www.wikidata.org/wiki/Q8091","display_name":"Grammar","level":2,"score":0.5881001949310303},{"id":"https://openalex.org/C114614502","wikidata":"https://www.wikidata.org/wiki/Q76592","display_name":"Combinatorics","level":1,"score":0.53816819190979},{"id":"https://openalex.org/C97212296","wikidata":"https://www.wikidata.org/wiki/Q338047","display_name":"Context-free grammar","level":3,"score":0.4291123151779175},{"id":"https://openalex.org/C2779343474","wikidata":"https://www.wikidata.org/wiki/Q3109175","display_name":"Context (archaeology)","level":2,"score":0.4263985753059387},{"id":"https://openalex.org/C118615104","wikidata":"https://www.wikidata.org/wiki/Q121416","display_name":"Discrete mathematics","level":1,"score":0.36764025688171387},{"id":"https://openalex.org/C41895202","wikidata":"https://www.wikidata.org/wiki/Q8162","display_name":"Linguistics","level":1,"score":0.23180881142616272},{"id":"https://openalex.org/C151730666","wikidata":"https://www.wikidata.org/wiki/Q7205","display_name":"Paleontology","level":1,"score":0.0},{"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}],"mesh":[],"locations_count":1,"locations":[{"id":"doi:10.1016/0166-218x(81)90006-8","is_oa":false,"landing_page_url":"https://doi.org/10.1016/0166-218x(81)90006-8","pdf_url":null,"source":{"id":"https://openalex.org/S171741597","display_name":"Discrete Applied Mathematics","issn_l":"0166-218X","issn":["0166-218X","1872-6771"],"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":"Discrete Applied Mathematics","raw_type":"journal-article"}],"best_oa_location":null,"sustainable_development_goals":[{"score":0.7300000190734863,"id":"https://metadata.un.org/sdg/4","display_name":"Quality Education"}],"awards":[],"funders":[],"has_content":{"pdf":false,"grobid_xml":false},"content_urls":null,"referenced_works_count":11,"referenced_works":["https://openalex.org/W1859552527","https://openalex.org/W1968788144","https://openalex.org/W1978427465","https://openalex.org/W1978532415","https://openalex.org/W2020151083","https://openalex.org/W2022022367","https://openalex.org/W2077372141","https://openalex.org/W4213117881","https://openalex.org/W6642567727","https://openalex.org/W6645285666","https://openalex.org/W6663801733"],"related_works":["https://openalex.org/W1924776930","https://openalex.org/W1984301931","https://openalex.org/W4230888127","https://openalex.org/W2299573515","https://openalex.org/W2054308287","https://openalex.org/W2063332329","https://openalex.org/W1989313238","https://openalex.org/W2186244857","https://openalex.org/W2131390643","https://openalex.org/W3037570608"],"abstract_inverted_index":null,"counts_by_year":[],"updated_date":"2025-11-06T03:46:38.306776","created_date":"2025-10-10T00:00:00"}
