Fairness in context Free grammars under canonical derivations

  • Sara Porat
  • Nissim Francez
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 182)


In [PFMZ 82] the notion of Fair derivations in context free grammars was introduced and studied. The main result there is a characterization of fairly terminating grammars as non-variable-doubling. In this paper we show that the same characterization is valid under canonical derivations in which the next variable to be expanded is deterministically chosen, leaving nondeterminism only to the decision as to which rule to apply. Two families of canonical derivations are introduced and studied: 1) Spinal derivations and 2) Layered derivations.


Context Free Grammar Full Cycle Derivation Tree Sentential Form Infinite Path 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. [H 84]
    D. Harel: "A general result about infinite trees and its applications", proc. 16th ACM-STOC, Washington D.C., May 1984.Google Scholar
  2. [HU 79]
    J.E. Hopcroft, J.D. Ulmann: "Introduction to automata theory, languages and computation", Addison-Wesley, Reading.Mass., 1979.Google Scholar
  3. [PFMZ 82]
    S. Porat, N. Francez, S. Moran, S. Zaks: "Fair derivations in context free grammars", Information and Control 55: 108–116, 1982.Google Scholar
  4. [RA 84]
    K.Rangarajan, S.Arun-kumar: "Fair derivations in EOL systems", submited for publication, 1984.Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1984

Authors and Affiliations

  • Sara Porat
    • 1
  • Nissim Francez
    • 1
  1. 1.Computer Science Department The TechnionHaifaIsrael

Personalised recommendations