Word-paired catenations of regular languages Original Research Article

In this paper, we mainly focus on the properties of word-paired catenations of regular languages and related languages. We propose a characterization of local regular languages from the viewpoint of word-paired catenation. We also investigate the properties of languages such that the word-paired catenations are regular-free. The languages, on condition that the word-paired catenations of these languages and their complements or reverses are regular, are studied too.