Regularized Beta Function
The regularized beta function is defined by
where
is the incomplete Beta Function and 
is the complete Beta Function.See also Beta Function, Regularized Gamma Function- Perfect Square
- Perfect Square Dissection
- Periapsis
- Perigon
- Perimeter
- Perimeter Polynomial
- Period Doubling
- Periodic Function
- Periodic Point
- Periodic Sequence
- Period Three Theorem
- Perkins' Quilt
- Perko Pair
- Permanence of Algebraic Form
- Permanence of Mathematical Relations Principle
- Permanent
- Permil
- Permutation
- Permutation Group
- Permutation Matrix
- Permutation Pseudotensor
- Permutation Symbol
- Permutation Tensor
- Peron Integral
- Perpendicular