Symbols:P

Prime Number

 * $p$

Used to denote a general prime number.

Probability

 * $p$

Used to denote a general probability.

As such, $p$ is a real number such that:


 * $0 \le p \le 1$

Power Set
$\powerset S$ is the power set of the set $S$.

It is defined as:
 * $\powerset S = \set {T: T \subseteq S}$

$\map {\mathfrak P} S$ is an alternative notation, but the "fraktur" font, of which $\mathfrak P$ is an example, is falling out of use, probably as a result of its difficulty in being both read and written.

Poisson Distribution

 * $X \sim \Poisson \lambda$

or
 * $X \sim \map {\operatorname {Pois} } \lambda$

$X$ has the Poisson distribution with parameter $\lambda$.

Probability Measure

 * $\Pr$

Probability Mass Function

 * $\map {p_X} x$