Given a finite alphabet and a language , the centralizer of is defined as the maximal language commuting with it. We prove that if the primitive root of the smallest word of (with respect to a lexicographic order) is prefix distinguishable in then the centralizer of is as simple as possible, that is, the submonoid . This lets us obtain a simple proof of a known result concerning the centralizer of nonperiodic three-word languages.
@article{ITA_2006__40_2_295_0, author = {Massazza, Paolo and Salmela, Petri}, title = {On the simplest centralizer of a language}, journal = {RAIRO - Theoretical Informatics and Applications - Informatique Th\'eorique et Applications}, volume = {40}, year = {2006}, pages = {295-301}, doi = {10.1051/ita:2006014}, mrnumber = {2252640}, zbl = {1112.68097}, language = {en}, url = {http://dml.mathdoc.fr/item/ITA_2006__40_2_295_0} }
Massazza, Paolo; Salmela, Petri. On the simplest centralizer of a language. RAIRO - Theoretical Informatics and Applications - Informatique Théorique et Applications, Tome 40 (2006) pp. 295-301. doi : 10.1051/ita:2006014. http://gdmltest.u-ga.fr/item/ITA_2006__40_2_295_0/
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