Results 1 to 10 of about 26 (26)

Infinitesimals via Cauchy sequences: Refining the classical equivalence

open access: yesOpen Mathematics, 2021
A refinement of the classic equivalence relation among Cauchy sequences yields a useful infinitesimal-enriched number system. Such an approach can be seen as formalizing Cauchy’s sentiment that a null sequence “becomes” an infinitesimal.
Bottazzi Emanuele, Katz Mikhail G.
doaj   +1 more source

Metric completions, the Heine-Borel property, and approachability

open access: yesOpen Mathematics, 2020
We show that the metric universal cover of a plane with a puncture yields an example of a nonstandard hull properly containing the metric completion of a metric space.
Kanovei Vladimir   +2 more
doaj   +1 more source

Monotone subsequence via ultrapower

open access: yesOpen Mathematics, 2018
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 ...
Błaszczyk Piotr   +3 more
doaj   +1 more source

Generalized solutions of variational problems and applications

open access: yesAdvances in Nonlinear Analysis, 2018
Ultrafunctions are a particular class of generalized functions defined on a hyperreal field ℝ*⊃ℝ{\mathbb{R}^{*}\supset\mathbb{R}} that allow to solve variational problems with no classical solutions.
Benci Vieri   +2 more
doaj   +1 more source

Courbure et Polygone de Newton [PDF]

open access: yes, 2009
2000 Mathematics Subject Classification: 26E35, 14H05, 14H20.The object of this article relates to the study of the complex algebraic curves by using the concept of envelope convex.
Mezaghcha, K., Hannachi M, M.
core  

Constructive Nonstandard Representations of Generalized Functions

open access: yes, 1998
Using techniques of nonstandard analysis Abraham Robinson showed that it is possible to represent each Schwartz distribution T as an integral T (OE) = R f OE, where f is some nonstandard smooth function.
Erik Palmgren
core  
Some of the next articles are maybe not open access.

Effective Infinitesimals in $\mathbb R$

Real Analysis Exchange, 2023
Mikhail Katz, Karel Hrbáček
exaly  

On the converse law of large numbers

Illinois Journal of Mathematics, 2020
Yeneng Sun, H Jérôme Keisler
exaly  

Formal multiplicative root series and algorithms of their evaluation

Communications in Algebra, 2021
Dariusz Bugajewski, Xiao-Xiong Gan
exaly  

A New Extension of the Riemann Integral

American Mathematical Monthly, 2018
C Bryan Dawson
exaly  

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