Definition:Real Number/Dedekind Cuts
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Definition
The set of rational numbers are identified with the set of rational cuts.
All other cuts are called, and are identified with, irrational numbers.
Notation
While the symbol $\R$ is the current standard symbol used to denote the set of real numbers, variants are commonly seen.
For example: $\mathbf R$, $\RR$ and $\mathfrak R$, or even just $R$.
Also known as
When the term number is used in general discourse, it is often tacitly understood as meaning real number.
They are sometimes referred to in the pedagogical context as ordinary numbers, so as to distinguish them from complex numbers
However, depending on the context, the word number may also be taken to mean integer or natural number.
Hence it is wise to be specific.
Also see
- Results about real numbers can be found here.
Sources
- 1964: Walter Rudin: Principles of Mathematical Analysis (2nd ed.) ... (previous) ... (next): Chapter $1$: The Real and Complex Number Systems: Real Numbers: $1.31$. Definition
- 1998: David Nelson: The Penguin Dictionary of Mathematics (2nd ed.) ... (previous) ... (next): real number
- 2008: David Nelson: The Penguin Dictionary of Mathematics (4th ed.) ... (previous) ... (next): real number