Mathematical Physics: Classical Mechanics
《Mathematical Physics: Classical Mechanics》 · 第 1 页 · Chapter 1，Definition 1.1
A link \(L\) of \(m\) components is a subset of \(S^3\), or of \(\mathbb R^3\), that consists of \(m\) disjoint, piecewise linear, simple closed curves. A link of one component is a knot.