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A Categorical Construction of Ultrafilters

Category Theory 2009-05-13 v2 General Mathematics General Topology

Abstract

Ultrafilters are useful mathematical objects having applications in nonstandard analysis, Ramsey theory, Boolean algebra, topology, and other areas of mathematics. In this note, we provide a categorical construction of ultrafilters in terms of the inverse limit of an inverse family of finite partitions; this is an elementary and intuitive presentation of a consequence of the profiniteness of Stone spaces. We then apply this construction to answer a question of Rosinger posed in arXiv:0709.0084v2 in the negative.

Keywords

Cite

@article{arxiv.0710.2497,
  title  = {A Categorical Construction of Ultrafilters},
  author = {Daniel Litt and Zachary Abel and Scott D. Kominers},
  journal= {arXiv preprint arXiv:0710.2497},
  year   = {2009}
}

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5 pages