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Related papers: Cantor versus Cantor

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A common question from students on the usual diagonalization proof for the uncountability of the set of real numbers is: when a representation of real numbers, such as the decimal expansions of real numbers, allows us to use the…

Discrete Mathematics · Computer Science 2015-01-07 Samuel C. Hsieh

In the present article, modeling certain rational numbers, that are represented in terms of Cantor series, are described. The statements on relations between digits in the representations of rational numbers by Cantor series (for the case…

Number Theory · Mathematics 2021-01-05 Symon Serbenyuk

Since the theory developed by Georg Cantor, mathematicians have taken a sharp interest in the sizes of infinite sets. We know that the set of integers is infinitely countable and that its cardinality is Aleph0. Cantor proved in 1891 with…

General Mathematics · Mathematics 2008-09-25 Laurent Germain

Based upon the axiom of choice it is proved that the cardinality of the rational numbers is not less than the cardinality of the irrational numbers. This contradicts a main result of transfinite set theory and shows that the axiom of choice…

General Mathematics · Mathematics 2009-09-29 W. Mueckenheim

The article is devoted to the alternating Cantor series. It is proved that any real number belonging to $[a_0-1;a_0]$, where $a_0=\sum^{\infty} _{k=1} {\frac{d_{2k}-1}{d_1d_2...d_{2k}}} $, has no more than two representations by the series…

Number Theory · Mathematics 2017-06-15 Symon Serbenyuk

Four constructions result from a desire to create enhancements to Cantor's infinite real set cardinality. Each continues to keep Cantor's cardinality formulation in place while providing new comparisons of arbitrary infinite sets. To…

General Mathematics · Mathematics 2026-04-24 William Johnston

Representing real numbers using convenient numeration systems (integer bases, $\beta$-numeration, Cantor bases, etc.) has been a longstanding mathematical challenge. This paper focuses on Cantor real bases and, specifically, on automatic…

Number Theory · Mathematics 2025-07-08 Émilie Charlier , Pierre Popoli , Michel Rigo

This article explores the model-dependent nature of set cardinality, emphasizing that cardinality is not absolute but varies across different axiomatic frameworks. Although Cantor's diagonal argument shows the real numbers are…

Logic · Mathematics 2025-06-10 Slavica Mihaljevic Vlahovic , Branislav Dobrasin Vlahovic

Bolzano and Cantor were the first mathematicians to make significant attempts to measure the size (numerosity) of different infinite collections. They differed in their methodological approaches, with Cantor's prevailing. This led to the…

General Mathematics · Mathematics 2024-03-28 Julian Jack

Several examples are used to illustrate how we deal cavalierly with infinities and unphysical systems in physics. Upon examining these examples in the context of infinities from Cantor's theory of transfinite numbers, the only known…

Mathematical Physics · Physics 2007-05-23 P. Narayana Swamy

This paper provides some counterexamples to Cantor's contributions to the foundations of Set Theory. The first counterexample forces Cantor's Diagonal Method (DM) to yield one of the numbers in the target list. To study this anomaly, and…

General Mathematics · Mathematics 2014-04-28 Enrique Coiras

A proof that the set of real numbers is denumerable is given.

General Mathematics · Mathematics 2013-07-17 Jailton C. Ferreira

In 1984, K. Mahler asked how well elements in the Cantor middle third set can be approximated by rational numbers from that set, and by rational numbers outside of that set. We consider more general missing digit sets $C$ and construct…

Number Theory · Mathematics 2019-11-11 Damien Roy , Johannes Schleischitz

A 1910 theorem of Brouwer characterizes the Cantor set as the unique totally disconnected, compact metric space without isolated points. A 1920 theorem of Sierpinski characterizes the rationals as the unique countable metric space without…

General Topology · Mathematics 2012-10-04 Michael Francis

The uncountability of $\mathbb{R}$ is one of its most basic properties, known far outside of mathematics. Cantor's 1874 proof of the uncountability of $\mathbb{R}$ even appears in the very first paper on set theory, i.e. a historical…

Logic · Mathematics 2023-06-26 Sam Sanders

We prove a Khintchine type theorem for approximation of elements in the Cantor set, as a subset of the formal Laurent series over $\mathbb{F}_3$, by rational functions of a specific type. Furthermore we construct elements in the Cantor set…

Number Theory · Mathematics 2014-09-02 Steffen Højris Pedersen

The uncountability of the reals was first established by Cantor in what was later heralded as the first paper on set theory. Since the latter constitutes the official foundations of mathematics, the logical study of the uncountability of…

Logic · Mathematics 2026-04-10 Dag Normann , Sam Sanders

The present article is devoted to representations of rational numbers in terms sign-variable Cantor expansions. The main attention is given to one of the discussions given by J. Galambos in [4].

Number Theory · Mathematics 2022-12-25 Symon Serbenyuk

In previous papers on this project a general static logical framework for formalizing and mechanizing set theories of different strength was suggested, and the power of some predicatively acceptable theories in that framework was explored.…

Logic in Computer Science · Computer Science 2023-06-22 Arnon Avron , Liron Cohen

Cantor's ordinal numbers, a powerful extension of the natural numbers, are a cornerstone of set theory. They can be used to reason about the termination of processes, prove the consistency of logical systems, and justify some of the core…

Logic in Computer Science · Computer Science 2025-10-22 Tom de Jong , Nicolai Kraus , Fredrik Nordvall Forsberg , Chuangjie Xu