Rational strong codes and structure of rational group languages
Let \(<A\); \(w_ i=v_ i|\) \(i\in I>\) be a finitely generated presentation, \(\Lambda\) be the identity of \(A^*\). The set [\(\Lambda\) ] of words congruent to \(\Lambda\) with respect to the congruence generated by \(\{(w_ i,v_ i)|\) \(i\in I\}\), is a free submonoid of \(A^*\), whose base is a strong code. We study rational strong codes. Using them, we give the structure of rational group languages.
scientific article; zbMATH DE number 4004488