Semantics of Quasi-Boolean Expressions

  • A. Bijlsma
Part of the Texts and Monographs in Computer Science book series (MCS)

Abstract

In deriving programs, it is often useful to consider certain expressions as well-defined although they contain subexpressions to which no value can reasonably be attributed. For instance, one wishes to consider the expression
$$ 0 \leqslant i < n and a\left[ i \right] = 0 $$
as false when i = n, without worrying whether or not n is in the subscript range of array a. Expressions like these are called quasi-boolean in [3]. Traditionally, they are treated by introducing the conditional connectives cand and cor [2, chapter 4] [4, §4.1].

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References

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    R. L. Barber. The Spine of Software. John Wiley & Sons, Chichester, 1987.Google Scholar
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    E. W. Dijkstra. A Discipline of Programming. Prentice-Hall, Englewood Cliffs, 1976.MATHGoogle Scholar
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    E. W. Dijkstra and W. H. J. Feijen. The linear search revisited. Struct. Prog., 10: 5–9, 1989.Google Scholar
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    D. Gries. The Science of Programming. Springer-Verlag, New-York, 1981.MATHGoogle Scholar
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    E. C. R. Hehner, L. E. Gupta, and A. J. Malton. Predicative methodology. Acta Informatica, 23: 487–505, 1986.MathSciNetMATHCrossRefGoogle Scholar

Copyright information

© Springer-Verlag New York, Inc. 1990

Authors and Affiliations

  • A. Bijlsma
    • 1
  1. 1.Department of Mathematics and Computing ScienceEindhoven University of TechnologyEindhovenThe Netherlands

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