Writhe

In knot theory, there are several competing notions of the quantity writhe, or Wr.

Description

In one sense, it is purely a property of an oriented link diagram and assumes integer values.

In another sense, it is a quantity that describes the amount of "coiling" of a mathematical knot (or any closed, simple curve) in three-dimensional space and assumes real numbers as values.

In both cases, writhe is a geometric quantity, meaning that while deforming a curve (or diagram) in such a way that does not change its topology, one may still change its writhe.

See also

• DNA supercoiling
• Knot (mathematics)
• Knot theory
• Link (knot theory)
• Linking number
• Ribbon theory
• Twist (mathematics)
• Winding number

External links

• Writhe @ Wikipedia