Towards a theory of recursive structures

  • David Harel
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 775)


In computer science, one is interested mainly in finite objects. Insofar as infinite objects are of interest, they must be computable, i.e., recursive, thus admitting an effective finite representation. This leads to the notion of a recursive graph, or, more generally, a recursive structure or data base. In this paper we summarize our recent work on recursive structures and data bases, including (i) the high undecidability of many problems on recursive graphs, (ii) somewhat surprising ways of deducing results on the classification of NP optimization problems from results on the degree of undecidability of their infinitary analogues, and (iii) completeness results for query languages on recursive data bases.


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Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • David Harel
    • 1
  1. 1.Dept. of Applied Mathematics and Computer ScienceThe Weizmann Institute of ScienceRehovotIsrael

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