Symbols:E

Hexadecimal

 * $\mathrm E$ or $\mathrm e$

The hexadecimal digit $14$.

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

Set

 * $E$

Used by some authors to denote a general set.

The $\LaTeX$ code for $E$ is E.

Identity Element

 * $e$

Used to indicate the identity element in a general algebraic structure.

If $e$ is the identity of the structure $\left({S, \circ}\right)$, 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

 * $e$

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

It is defined to be the unique real number such that the value of the 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.

Experiment

 * $\mathcal E$

The $\LaTeX$ code for $\mathcal E$ is \mathcal E.

Expectation

 * $E \left({X}\right)$

The $\LaTeX$ code for $E \left({X}\right)$ is E \left({X}\right).

Conditional Expectation

 * $E \left({X | B}\right)$

The $\LaTeX$ code for $E \left({X | B}\right)$ is E \left({X | B}\right).