Extreme solutions of equations

  • Edsger W. Dijkstra
Conference paper
Part of the NATO ASI Series book series (volume 36)


In the previous chapter we have encountered a number of statements S, for which the predicate transformers wlp(S,?) and wp(S,?) were given in closed form. In the next chapter we shall encounter a statement for which the predicates wlp(S,X) and wp(S,X) are given as solutions of equations of the form
$${\text{Y }}:{\text{ }}\left[ {{\text{b}}.\left( {{\text{X}},{\text{Y}}} \right)} \right].$$

Here, b is a function from predicate pairs to predicates, i.e. b.(X,Y) is a boolean structure, [b.(X,Y)] is a boolean expression in X and Y , which for given X and Y is either true or false.




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Copyright information

© Springer-Verlag Berlin Heidelberg 1987

Authors and Affiliations

  • Edsger W. Dijkstra
    • 1
  1. 1.Department of Computer SciencesThe University of Texas at AustinAustinUSA

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