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Transactions of the American Mathematical Society

Published by the American Mathematical Society, the Transactions of the American Mathematical Society (TRAN) is devoted to research articles of the highest quality in all areas of pure and applied mathematics.

ISSN 1088-6850 (online) ISSN 0002-9947 (print)

The 2020 MCQ for Transactions of the American Mathematical Society is 1.43.

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End extensions, conservative extensions, and the Rudin-Frolík ordering
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by Andreas Blass PDF
Trans. Amer. Math. Soc. 225 (1977), 325-340 Request permission

Abstract:

The ordering of ultrafilters on the natural numbers defined by “E-prod N is an end extension of D-prod N,” the ordering defined by “E-prod N is a conservative extension of D-prod N,” and the Rudin-Frolik ordering are proved to be distinct if the continuum hypothesis holds. These three orderings are also characterized in terms of (not necessarily internal) ultrafilters in the Boolean algebra of internal sets of natural numbers in a nonstandard universe.
References
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Additional Information
  • © Copyright 1977 American Mathematical Society
  • Journal: Trans. Amer. Math. Soc. 225 (1977), 325-340
  • MSC: Primary 02H13; Secondary 04A05
  • DOI: https://doi.org/10.1090/S0002-9947-1977-0424556-X
  • MathSciNet review: 0424556