nLab
knot invariant

Contents

Idea

A knot invariant is map from isotopy equivalence classes of knots to any kind of structure you could imagine. These are helpful because it is much easier to check that the structures one maps to (numbers, groups, etc.) are different than it is to check that knots are different.

Examples

Many of these extend to link invariants or have variants that depend on the knot being oriented.

category: knot theory

Revised on December 5, 2011 20:22:33 by Tim Porter (95.147.237.179)