23.4.6.1类模板集概述[set.overview]

@H_301_2@A set satisfies all of the requirements of [..] an associative
container (23.2.4) […]

@H_301_2@因为它满足了23.2.4中描述的作为关联容器的所有前提条件.并不像“将一个键映射到一个值”那么简单.

@H_301_2@第二段甚至强调了这一点(或者更确切地说,事实上,映射和多重映射在关联容器上具有附加功能)：

@H_301_2@23.2.4关联容器[associative.reqmts]

@H_301_2@2) Each associative container is parameterized on Key and an ordering relation Compare that induces a strict
weak ordering (25.4) on elements of Key. In addition,map and multimap associate an arbitrary type T with
the Key. The object of type Compare is called the comparison object of a container.

@H_301_2@完整的段落太大,无法在这里重现.