Absolute Square
Also known as the squared Norm. The absolute square of a Complex Number 
is written 
and isdefined as
 | (1) |
denotes the Complex Conjugate of . For a Real Number, (1) simplifies to | (2) |
, then the absolute square can be written | (3) |
An important identity involving the absolute square is given by
 |  |  | |
|  | ||
|  | (4) |
If
, then (4) becomes | |  | |
|  | ||
|  | ||
|  | (5) |
If
, and 
, then | (6) |
 | |  | |
|  | ||
|  | ||
|  | (7) |
- Joachimsthal's Equation
- Johnson Circle
- Johnson's Equation
- Johnson Solid
- Johnson's Theorem
- Join (Graph)
- Join (Spaces)
- Joint Distribution Function
- Joint Probability Density Function
- Joint Theorem
- Jonah Formula
- Jones Polynomial
- Jonquière's Function
- Jordan Algebra
- Jordan Curve
- Jordan Curve Theorem
- Jordan Decomposition Theorem
- Jordan-Hölder Theorem
- Jordan Measure
- Jordan Polygon
- Jordan's Inequality
- Jordan's Lemma
- Josephus Problem
- Jug
- Jugendtraum