Equal
Two quantities are said to be equal if they are, in some well-defined sense, equivalent. Equality of quantities 
and
is written 
.
A symbol with three horizontal line segments (
) resembling the equals sign is used to denote bothequality by definition (e.g., 
means 
is Defined to be equal to 
) and Congruence(e.g., 
means 13 divided by 12 leaves a Remainder of 1--a fact known to all readersof analog clocks).
- Plouffe's Constant
- Plumbing
- Pluperfect Number
- Plurisubharmonic Function
- Plus
- Plus or Minus
- Plus Perfect Number
- Plus Sign
- Plutarch Numbers
- Plücker Characteristics
- Plücker Relations
- Plücker's Conoid
- Plücker's Equations
- Pochhammer Symbol
- Pocklington-Lehmer Test
- Pocklington's Criterion
- Pocklington's Theorem
- Poggendorff Illusion
- Pohlke's Theorem
- Poincaré-Birkhoff Fixed Point Theorem
- Poincaré Conjecture
- Poincaré Duality
- Poincaré Formula
- Poincaré-Fuchs-Klein Automorphic Function
- Poincaré Group