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Related papers: Countability of the Real Numbers

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Remarks on the Cantor's nondenumerability proof of 1891 that the real numbers are noncountable will be given. By the Cantor's diagonal procedure, it is not possible to build numbers that are different from all numbers in a general assumed…

General Mathematics · Mathematics 2007-05-23 Slavica Vlahovic , Branislav Vlahovic

Cantor's famous proof of the non-denumerability of real numbers does apply to any infinite set. The set of exclusively all natural numbers does not exist. This shows that the concept of countability is not well defined. There remains no…

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

The uncountability of the real numbers is one of their most basic properties, known (far) outside of mathematics. Cantor's 1874 proof of the uncountability of the real numbers even appears in the very first paper on set theory, i.e. a…

Logic · Mathematics 2022-06-28 Sam Sanders

For any particularly interesting theorem one proof is never enough. Instead, the first proof sets the challenge to find a more elegant method that illuminates subtle features of the math, is simpler to understand, or even avoids using…

History and Overview · Mathematics 2014-01-23 Christina Knapp , Cesar E. Silva

This paper examines the possibilities of extending Cantor's two arguments on the uncountable nature of the set of real numbers to one of its proper denumerable subsets: the set of rational numbers. The paper proves that, unless certain…

General Mathematics · Mathematics 2012-01-26 Antonio Leon

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

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

We apply an inductive argument to three theorems of Cantor on (1) the uncountability of infinite binary sequences, (2) the uncountability of real numbers, and (3) the non-equinumerosity of sets with their powersets. This technique proves…

Logic · Mathematics 2025-10-20 Saeed Salehi

This article critically reappraises arguments in support of Cantor's theory of transfinite numbers. The following results are reported: i) Cantor's proofs of nondenumerability are refuted by analyzing the logical inconsistencies in…

General Mathematics · Mathematics 2010-02-25 J. A. Perez

This somewhat unusual proof for the fact that the reals are uncountable, which is adapted from one of Bourbaki's proofs in "Fonctions d'une variable reelle", may be of some interest.

History and Overview · Mathematics 2009-01-06 Eliahu Levy

It is shown that the pillars of transfinite set theory, namely the uncountability proofs, do not hold. (1) Cantor's first proof of the uncountability of the set of all real numbers does not apply to the set of irrational numbers alone, and,…

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

It is shown that any denumerable list L to which Cantor's diagonal method was applied is incomplete. However, this doesn't allow us to affirm that the cardinality of the real numbers of the interval [0, 1] is greater than the cardinality of…

General Mathematics · Mathematics 2007-05-23 Jailton C. Ferreira

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

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

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

In 1891 Cantor presented two proofs with the purpose to establish a general theorem that any set can be replaced by a set of greater power. Cantor's power set theorem can be considered to be an extension of Cantor's 1891 second proof and…

General Mathematics · Mathematics 2007-05-23 Paola Cattabriga

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

In which a review of the concept of countability is done in mathematics, subjecting review some of the theorems so far accepted, showing their inconsistency and also taking concrete elements on the countability of all the powers of the set…

General Mathematics · Mathematics 2016-01-07 Denis Martínez Tápanes

The concept of ``countable set'' is attributed to Georg Cantor, who set the boundary between countable and uncountable sets in 1874. The concept of ``computable set'' arose in the study of computing models in the 1930s by the founders of…

Computational Complexity · Computer Science 2024-06-14 Hantao Zhang

For more than a century, Cantor's theory of transfinite numbers has played a pivotal role in set theory, with ramifications that extend to many areas of mathematics. This article extends earlier findings with a fresh look at the critical…

General Mathematics · Mathematics 2023-05-17 Juan A Perez

We give an uncountability proof of the reals which relies on their order completeness instead of their sequential completeness. We use neither a form of the axiom of choice nor the law of excluded middle, therefore the proof applies to the…

History and Overview · Mathematics 2019-02-21 Ingo Blechschmidt , Matthias Hutzler
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