PossibleZeroQ[expr] gives True if basic symbolic and numerical methods suggest that expr has value zero, and gives False otherwise.

PowerDistribution[k, a] represents a power distribution with domain parameter k and shape parameter a.

PowersRepresentations[n, k, p] gives the distinct representations of the integer n as a sum of k non-negative p\[Null]^th integer powers.

PrecisionGoal is an option for various numerical operations which specifies how many effective digits of precision should be sought in the final result.

Precision[x] gives the effective number of digits of precision in the number x.

PreferencesPath is a global option that specifies which directories are searched for user-specific settings when Mathematica is started.

PreserveImageOptions is an option to graphics and related functions that specifies whether image size and certain other options should be preserved from the previous version ...

PrimePowerQ[expr] yields True if expr is a power of a prime number, and yields False otherwise.

PrimeQ[expr] yields True if expr is a prime number, and yields False otherwise.

Primes represents the domain of prime numbers, as in x \[Element] Primes.