Symplectic Geometry
《Symplectic Geometry》 · 第 96、189 页 · Section 4.9 的 trivial tangle 定义与 Section 8.1 的 rational tangle 定义
An \(n\)-tangle is trivial if it is homeomorphic to a cylinder \(D^2\times[0,1]\) containing \(n\) parallel straight lines, each connecting the top to the bottom (there are no loops in a trivial tangle). […] A rational tangle is homeomorphic to the trivial 2-tangle. This means that it can be “unwound” by sliding the endpoints around on the boundary sphere.