Irrotational Field
A Vector Field 
for which the Curl vanishes,
See also Beltrami Field, Conservative Field, Solenoidal Field, Vector Field
- Rational Triangle
- Ratio Test
- RATS Sequence
- Ray
- Rayleigh Differential Equation
- Rayleigh Distribution
- Rayleigh-Ritz Variational Technique
- Rayleigh's Formulas
- Rayleigh's Theorem
- Real Analysis
- Real Axis
- Real Function
- Realizer
- Real Line
- Real Matrix
- Real Number
- Real Part
- Real Polynomial
- Real Projective Plane
- Real Quadratic Field
- Rearrangement Theorem
- Reciprocal
- Reciprocal Difference
- Reciprocal Polyhedron
- Reciprocating Sphere