Writhe
Also called the Twist Number. The sum of crossings 
of a Link 
,
where
defined to be 
if the overpass slants from top left to bottom right or bottom left to topright and 
is the set of crossings of an oriented Link. If a Knot 
is Amphichiral, then
(Thistlethwaite). Letting Lk be the Linking Number of the two components of a ribbon, Tw be theTwist, and Wr be the writhe, then
(Adams 1994, p. 187).See also Screw, Twist
References
Adams, C. C. The Knot Book: An Elementary Introduction to the Mathematical Theory of Knots. New York: W. H. Freeman, 1994.
- Ramanujan Cos/Cosh Identity
- Ramanujan-Eisenstein Series
- Ramanujan Function
- Ramanujan g- and G-Functions
- Ramanujan-Petersson Conjecture
- Ramanujan Psi Sum
- Ramanujan's Hypergeometric Identity
- Ramanujan's Hypothesis
- Ramanujan's Identity
- Ramanujan's Integral
- Ramanujan's Interpolation Formula
- Ramanujan's Master Theorem
- Ramanujan's Square Equation
- Ramanujan's Sum
- Ramanujan's Sum Identity
- Ramanujan's Tau-Dirichlet Series
- Ramanujan's Tau Function
- Ramanujan Theta Functions
- Ramp Function
- Ramphoid Cusp
- Ramsey Number
- Ramsey's Theorem
- Randelbrot Set
- Random Distribution
- Random Dot Stereogram