Extended Chomsky-Schützenberger theorems

  • Franz-Josef Brandenburg
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 140)


The operations of a homomorphic equality and an inverse homomorphic equality are introduced. These operations are obtained from n-tuples of homomorphisms, incorporating the notion of an equality set. For one-tuples they are a homomorphism and an inverse homomorphism. Homomorphic equality and inverse homomorphic equality operations provide simple and uniform characterizations of the recursively enumerable sets in terms of the regular sets, and of classes H(L λ MR) in terms of L. These characterizations resemble the Chomsky-Schützenberger theorem for context-free languages.


Small Class Input String Canonical Extension Input Tape Formal Language Theory 
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Copyright information

© Springer-Verlag Berlin Heidelberg 1982

Authors and Affiliations

  • Franz-Josef Brandenburg
    • 1
  1. 1.Institut für InformatikUniversität BonnBonnFederal Republic of Germany

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