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Bibliographic Details
Main Authors: Alexander, Samuel Allen, Dawson, Bryan
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2411.14689
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author Alexander, Samuel Allen
Dawson, Bryan
author_facet Alexander, Samuel Allen
Dawson, Bryan
contents In the hyperreals constructed using a free ultrafilter on R, where [f] is the hyperreal represented by f:R->R, it is tempting to define a derivative operator by [f]'=[f'], but unfortunately this is not generally well-defined. We show that if the ultrafilter in question is idempotent and contains (0,epsilon) for arbitrarily small real epsilon then the desired derivative operator is well-defined for all f such that [f'] exists. We also introduce a hyperreal variation of the derivative from finite calculus, and show that it has surprising relationships to the standard derivative. We give an alternate proof, and strengthened version of, Hindman's theorem.
format Preprint
id arxiv_https___arxiv_org_abs_2411_14689
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Hyperreal differentiation with an idempotent ultrafilter
Alexander, Samuel Allen
Dawson, Bryan
Logic
26E35, 26A24
In the hyperreals constructed using a free ultrafilter on R, where [f] is the hyperreal represented by f:R->R, it is tempting to define a derivative operator by [f]'=[f'], but unfortunately this is not generally well-defined. We show that if the ultrafilter in question is idempotent and contains (0,epsilon) for arbitrarily small real epsilon then the desired derivative operator is well-defined for all f such that [f'] exists. We also introduce a hyperreal variation of the derivative from finite calculus, and show that it has surprising relationships to the standard derivative. We give an alternate proof, and strengthened version of, Hindman's theorem.
title Hyperreal differentiation with an idempotent ultrafilter
topic Logic
26E35, 26A24
url https://arxiv.org/abs/2411.14689