Jürgensen, H.; Salomaa, K.; Yu, S. Decidability of the intercode property. (English) Zbl 0824.68061 J. Inf. Process. Cybern. 29, No. 6, 375-380 (1993). Summary: A language \(L\) over an alphabet \(X\) is said to be an intercode of index \(m\) if \(L^{m + 1} \cap X^ + L^ mX^ + = \emptyset\). For any fixed index \(m\) it is obviously decidable whether a regular language is an intercode of index \(m\). On the other hand, it has been an open question whether it is decidable for a regular language if there is an index \(m\) such that the language is an intercode of that index \(m\). We answer this question in the affirmative. Cited in 4 Documents MSC: 68Q45 Formal languages and automata Keywords:intercode; regular language PDFBibTeX XMLCite \textit{H. Jürgensen} et al., J. Inf. Process. Cybern. 29, No. 6, 375--380 (1993; Zbl 0824.68061)