The paper establishes a strong correspondence between two important clustering approaches that emerged in the 1970's: clustering by level sets or cluster tree as proposed by Hartigan and clustering by gradient lines or gradient flow as proposed by Fukunaga and Hostetler. We do so by showing that we can move up the cluster tree by following the gradient ascent flow.

翻译：本文在1970年代出现的两种重要的集群办法之间建立了强烈的对应关系:按照Hartigan的建议,按级组或集群树进行分组;按照Fukunaga和Hostetler的建议,按梯度线或梯度流进行分组。我们通过表明我们可以沿着梯度向上移动,从而向上移动集群树。