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Additional information
These results were presented to the American Mathematical Society in New York City on April 21, 1973. Some of the results were obtained while on a Visiting Professorship at Rutgers University. We are grateful to the Rutgers Mathematics Department for its hospitality, and to Joseph G. Rosenstein for useful discussions.
University of Illinois at Chicago Circle, Published in Algebra i Logika, Vol. 12, No. 6, pp. 713–729, November–December, 1973.
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Hay, L. Index sets in0′. Algebr Logic 12, 408–416 (1973). https://doi.org/10.1007/BF02218733
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DOI: https://doi.org/10.1007/BF02218733