Symbols:R

Set of Real Numbers

 * $\R$

The set of real numbers.

$\LaTeX$ also allows, but  does not recognise that as a valid code.

Some authors use $R$.

Set of Non-Zero Real Numbers

 * $\R_{\ne 0}$

The set of non-zero real numbers:
 * $\R_{\ne 0} = \R \setminus \set 0$

$\LaTeX$ also allows, but  does not recognise that as a valid code.

Deprecated

 * $\R^*$

The set of non-zero real numbers:
 * $\R^* = \R \setminus \left\{{0}\right\}$

$\LaTeX$ also allows, but  does not recognise that as a valid code.

Set of Non-Negative Real Numbers

 * $\R_{\ge 0}$

The set of non-negative real numbers:
 * $\R_{\ge 0} = \set {x \in \R: x \ge 0}$

$\LaTeX$ also allows, but  does not recognise that as a valid code.

Deprecated

 * $\R_+$

The set of non-negative real numbers:
 * $\R_+ = \left\{{x \in \R: x \ge 0}\right\}$

$\LaTeX$ also allows, but  does not recognise that as a valid code.

Set of Strictly Positive Real Numbers

 * $\R_{> 0}$

The set of strictly positive real numbers:
 * $\R_{> 0} = \set {x \in \R: x > 0}$

$\LaTeX$ also allows, but  does not recognise that as a valid code.

Deprecated

 * $\R_+^*$

The set of strictly positive real numbers:
 * $\R_+^* = \left\{{x \in \R: x > 0}\right\}$

$\LaTeX$ also allows, but  does not recognise that as a valid code.

Extended Set of Real Numbers

 * $\overline \R$

The extended set of real numbers:


 * $\overline \R = \R \cup \set {+\infty, -\infty}$

$\LaTeX$ also allows, but  does not recognise that as a valid code.

Real Part

 * $\map \Re z$ or $\map {\operatorname {Re} } z$

The real part of a complex number $z$.

Variants
Variants of $\map {\operatorname {Re} } z$ and $\map \Re z$ that can often be found are:


 * $\map {\operatorname {\mathscr R} } z$
 * $\map {\operatorname {re} } z$