Salomaa, Arto Subword balance in binary words, languages and sequences. (English) Zbl 1108.68072 Fundam. Inform. 75, No. 1-4, 469-482 (2007). Summary: We investigate binary words and languages having a balanced structure of scattered) subwords. We introduce a “difference function” \(D\) for binary words. For \(D=0\), the resulting language is properly context-sensitive. Parikh matrices constitute a useful technical tool in the study, we investigate also the independence of their entries. The investigation is extended to concern \(\omega\)-words and periodicity. For the Fibonacci word, the \(D\)-values are in many ways connected with the Fibonacci numbers. Cited in 4 Documents MSC: 68Q45 Formal languages and automata 68R15 Combinatorics on words Keywords:Parikh matrix; Fibonacci word PDFBibTeX XMLCite \textit{A. Salomaa}, Fundam. Inform. 75, No. 1--4, 469--482 (2007; Zbl 1108.68072)