Special units are a sort of predecessor of Euler systems, and they are mainly used to obtain annihilators for class groups. So one is interested in finding as many special units as possible (actually we use a technical generalization called “semispecial”). In this paper we show that in any abelian field having a real genus field in the narrow sense all Washington units are semispecial, and that a slightly weaker statement holds true for all abelian fields. The group of Washington units is very often larger than Sinnott’s group of cyclotomic units. In a companion paper we will show that in concrete families of abelian fields the group of Washington units is much larger than that of Sinnott units, by giving lower bounds on the index. Combining this with the present paper gives strong annihilation results.

中文翻译：

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华盛顿部队、半特种部队和阶级团体的歼灭

特殊单位是欧拉系统的一种前身，主要用于为阶级群体获取歼灭者。因此，人们有兴趣找到尽可能多的特殊单位（实际上我们使用一种称为“半特殊”的技术概括）。在本文中，我们证明了在任何具有狭义真属域的阿贝尔域中，所有华盛顿单位都是半特殊的，并且稍微弱一点的陈述适用于所有阿贝尔域。华盛顿单位群通常比辛诺特的分圆单位群大。在一篇配套论文中，我们将通过给出指数的下限来证明在阿贝尔域的具体族中，华盛顿单位群比 Sinnott 单位群大得多。将此与本论文相结合，给出了强烈的湮灭结果。