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Boolean combinations of r.e. open sets

Published online by Cambridge University Press:  12 March 2014

Louise Hay*
Affiliation:
University of Illinois at Chicago Circle, Chicago, Illinois 60680

Extract

In [2], [3], J. Grassin characterized those classes of sets which are expressible as a Boolean combination of open sets in the Baire topology on the power set of the natural numbers. From this characterization he deduced that if is a Boolean combination of recursive open sets, then the minimum length for any Boolean combination representing can be realized using recursive open sets.

Type
Research Article
Copyright
Copyright © Association for Symbolic Logic 1976

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References

REFERENCES

[1] Ershov, Y. L., A hierarchy of sets. I, Algebra and Logic, vol. 7 (1968), pp. 2543.CrossRefGoogle Scholar
[2] Grassin, J., Ensembles d'indices des combinaisons booléennes d'ouverts dont une clé est recursivement énumérable, Thesis, Université d'Orléans, 1972.Google Scholar
[3] Grassin, J., Index sets in Ershov's hierarchy, this Journal, vol. 39 (1974), pp. 97104.Google Scholar
[4] Kuratowski, K., Topology, vol. I, Academic Press, New York, 1966.Google Scholar
[5] Rogers, H. Jr., Theory of recursive functions and effective computability, McGraw-Hill, New York, 1967.Google Scholar