无穷（Infinity）是什么？

    众所周知，数学是关于无穷的学问。这是基本知识。

请读者仔细研读无穷的维基内容：（了解大概即可！）

Contents

1 History

1.1 Early Greek

1.2 Early Indian

1.3 17th century

2 Mathematics

2.1 Infinity symbol

2.2 Calculus（微积分）

2.2.1 Real analysis（实分析）

2.2.2 Complex analysis

2.3 Nonstandard analysis（非标准分析）

2.4 Set theory

2.4.1 Cardinality of the continuum

2.5 Geometry and topology

2.6 Fractals

2.7 Mathematics without infinity

3 Physics

3.1 Theoretical applications of physical infinity

3.2 Cosmology

4 Logic

5 Computing

6 Arts, games, and cognitive sciences

7 See also

8 Notes

9 References

10 Sources

11 External links

袁萌  陈启清  元月3日

附件：

The infinity symbol

Infinity (symbol: ∞) is a concept describing something without any bound, or something larger than any natural number. Philosophers have speculated about the nature of the infinite, for example Zeno of Elea, who proposed many paradoxes involving infinity, and Eudoxus of Cnidus, who used the idea of infinitely small quantities in his method of exhaustion. Modern mathematics uses the general concept of infinity in the solution of many practical and theoretical problems, such as in calculus and set theory, and the idea is also used in physics and the other sciences.

In mathematics, "infinity" is often treated as a number (i.e., it counts or measures things: "an infinite number of terms") but it is not the same sort of number as either a natural or a real number.

Georg Cantor formalized many ideas related to infinity and infinite sets during the late 19th and early 20th centuries. In the theory he developed, there are infinite sets of different sizes (called cardinalities).[1] For example, the set of integers is countably infinite, while the infinite set of real numbers is uncountable.[2]

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