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The main result shows that this problem is decidable for all (integer and half) levels of the Straubing\u2013Th\u00e9rien hierarchy.<\/jats:p>","DOI":"10.1515\/forum-2016-0028","type":"journal-article","created":{"date-parts":[[2017,9,6]],"date-time":"2017-09-06T10:00:59Z","timestamp":1504692059000},"page":"663-679","source":"Crossref","is-referenced-by-count":4,"title":["The \u03c9-inequality problem for concatenation hierarchies of star-free languages"],"prefix":"10.1515","volume":"30","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-3829-2382","authenticated-orcid":false,"given":"Jorge","family":"Almeida","sequence":"first","affiliation":[{"name":"CMUP , Departamento de Matem\u00e1tica , Faculdade de Ci\u00eancias , Universidade do Porto , Rua do Campo Alegre 687, 4169-007 Porto , Portugal"}]},{"given":"Ond\u0159ej","family":"Kl\u00edma","sequence":"additional","affiliation":[{"name":"Department of Mathematics and Statistics , Masaryk University , Kotl\u00e1\u0159sk\u00e1 2, 611 37 Brno , Czech Republic"}]},{"given":"Michal","family":"Kunc","sequence":"additional","affiliation":[{"name":"Department of Mathematics and Statistics , Masaryk University , Kotl\u00e1\u0159sk\u00e1 2, 611 37 Brno , Czech Republic"}]}],"member":"374","published-online":{"date-parts":[[2017,9,6]]},"reference":[{"key":"2023033115245727929_j_forum-2016-0028_ref_001_w2aab3b7ab1b6b1ab1b9b1Aa","doi-asserted-by":"crossref","unstructured":"J.  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