Monotone subsequence via ultrapower

Piotr Błaszczyk, Vladimir Kanovei, Mikhail G. Katz, Tahl Nowik

Research output: Contribution to journalArticlepeer-review

Abstract

An ultraproduct can be a helpful organizing principle in presenting solutions of problems at many levels, as argued by Terence Tao. We apply it here to the solution of a calculus problem: every infinite sequence has a monotone infinite subsequence, and give other applications.

Original languageEnglish
Pages (from-to)149-153
Number of pages5
JournalOpen Mathematics
Volume16
Issue number1
DOIs
StatePublished - 2018

Keywords

  • Compactness
  • Monotone subsequence
  • Ordered structures
  • Saturation
  • Ultrapower

All Science Journal Classification (ASJC) codes

  • General Mathematics

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