Sgn
Also called Signum. It can be defined as
 | (1) |
 | (2) |
is the Heaviside Step Function. For 
, this can be written | (3) |
- Rank (Statistics)
- Rank (Tensor)
- Ranunculoid
- RAT-Free Set
- Ratio
- Ratio Distribution
- Rational Approximation
- Rational Canonical Form
- Rational Cuboid
- Rational Distances
- Rational Domain
- Rational Double Point
- Rational Function
- Rational Integer
- Rational Number
- Rational Point
- Rational Quadrilateral
- Rational Triangle
- Ratio Test
- RATS Sequence
- Ray
- Rayleigh Differential Equation
- Rayleigh Distribution
- Rayleigh-Ritz Variational Technique
- Rayleigh's Formulas