On complements of unary L languages

摘要

We characterize a special class of developmental languages generated by unary 〈1, 0〉 systems. By choosing appropriate members of this class we can immediately prove that the family of propagating unary 〈1, 0〉 languages is not closed in the family of FTIL languages under union, intersection, and complementation. The constructions generalize and extend an earlier result of Ruohonen in relation to an open problem of Rosenberg and Lee for IL languages.