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Identity Element


Denotes the identity element in a general algebraic structure.

If $e$ is the identity of the structure $\struct {S, \circ}$, then a subscript is often used: $e_S$.

This is particularly common when more than one structure is under discussion.

The $\LaTeX$ code for \(e_S\) is e_S .

Euler's Number


Euler's number $e$ is the base of the natural logarithm $\ln$.

$e$ is defined to be the unique real number such that the value of the (real) exponential function $e^x$ has the same value as the slope of the tangent line to the graph of the function.

The $\LaTeX$ code for \(e\) is e .



Used to denote the eccentricity of a conic section.

The $\LaTeX$ code for \(e\) is e .


$\mathrm E$

The Système Internationale d'Unités symbol for the metric scaling prefix exa, denoting $10^{\, 18 }$, is $\mathrm { E }$.

Its $\LaTeX$ code is \mathrm {E} .


$\mathrm E$ or $\mathrm e$

The hexadecimal digit $14$.

Its $\LaTeX$ code is \mathrm E  or \mathrm e.


$\mathrm E$

The duodecimal digit $11$.

Its $\LaTeX$ code is \mathrm E .



Used by some authors to denote a general set.

The $\LaTeX$ code for \(E\) is E .

Complete Elliptic Integral of the Second Kind

$\map E k$

$\ds \map E k = \int \limits_0^{\pi / 2} \sqrt {1 - k^2 \sin^2 \phi} \rd \phi$

is the complete elliptic integral of the second kind, and is a function of $k$, defined on the interval $0 < k < 1$.

The $\LaTeX$ code for \(\map E k\) is \map E k .


$\mathcal E$

An experiment, which can conveniently be denoted $\EE$, is a probability space $\struct {\Omega, \Sigma, \Pr}$.

The $\LaTeX$ code for \(\mathcal E\) is \mathcal E  or \EE.


$\expect X$

Let $\struct {\Omega, \Sigma, \Pr}$ be a probability space.

Let $X$ be a real-valued discrete random variable on $\struct {\Omega, \Sigma, \Pr}$.

The expectation of $X$, written $\expect X$, is defined as:

$\expect X := \ds \sum_{x \mathop \in \image X} x \map \Pr {X = x}$

whenever the sum is absolutely convergent, that is, when:

$\ds \sum_{x \mathop \in \image X} \size {x \map \Pr {X = x} } < \infty$

The $\LaTeX$ code for \(\expect X\) is \expect X .

Conditional Expectation

$\expect {X \mid B}$

Let $\struct {\Omega, \Sigma, \Pr}$ be a probability space.

Let $X$ be a discrete random variable on $\struct {\Omega, \Sigma, \Pr}$.

Let $B$ be an event in $\struct {\Omega, \Sigma, \Pr}$ such that $\map \Pr B > 0$.

The conditional expectation of $X$ given $B$ is written $\expect {X \mid B}$ and defined as:

$\expect {X \mid B} = \ds \sum_{x \mathop \in \image X} x \condprob {X = x} B$


$\condprob {X = x} B$ denotes the conditional probability that $X = x$ given $B$

whenever this sum converges absolutely.

The $\LaTeX$ code for \(\expect {X \mid B}\) is \expect {X \mid B} .


$\mathrm E$

East (Terrestrial)

East is the direction on (or near) Earth's surface along the small circle in the direction of Earth's rotation in space about its axis.

East (Celestial)

Definition:East (Celestial)

The $\LaTeX$ code for \(\mathrm E\) is \mathrm E .



The usual symbol used to denote the energy of a body is $E$.

Its $\LaTeX$ code is E .

Electric Field Strength

$\mathbf E$

The usual symbol used to denote electric field strength is $\mathbf E$.

Its $\LaTeX$ code is \mathbf E .

Electromotive Force


The usual symbol used to denote electromotive force is $\EE$.

Its $\LaTeX$ code is \EE .

Elementary Charge


The symbol used to denote the elementary charge is usually $\E$ or $e$.

The preferred symbol on $\mathsf{Pr} \infty \mathsf{fWiki}$ is $\E$.

Its $\LaTeX$ code is \E .

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