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arXiv math/0001056math.ATmath.KT
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导出范畴中Brown可表示性的失败

Failure of Brown representability in derived categories

J. Daniel Christensen, Bernhard Keller, Amnon Neeman

摘要:

设T是一个有上积的三角范畴,C是T中紧对象的满子范畴.如果T是谱的同伦范畴,Adams在[Adams 71]中证明了:所有的逆变同调函子C --> Ab是T上可表示函子的限制,所有的自然变换是T中态射的限制。这在多大程度上适用于其他三角分类,一直是个谜。在[Neeman 97]中,证明了只要C是可数的,亚当斯定理仍然成立,但通常可能失败。失败的表现是,可以有自然变换,而不是从地图在T。一个令人困惑的开放问题仍然存在:是每一个同调函子的限制,一个可表示函子的T?在最近的一篇论文中,Bkillannis取得了一些进展。但在本文中,我们解决了这个问题。有环的导出范畴T = D(R)和逆变同调函子C --> Ab的例子,它们不是可表示的限制。

英文摘要:

Let T be a triangulated category with coproducts, C the full subcategory of compact objects in T. If T is the homotopy category of spectra, Adams proved the following in [Adams71]: All contravariant homological functors C --> Ab are the restrictions of representable functors on T, and all natural transformations are the restrictions of morphisms in T. It has been something of a mystery, to what extent this generalises to other triangulated categories. In [Neeman97], it was proved that Adams' theorem remains true as long as C is countable, but can fail in general. The failure exhibited was that there can be natural transformations not arising from maps in T. A puzzling open problem remained: Is every homological functor the restriction of a representable functor on T? In a recent paper, Beligiannis made some progress. But in this article, we settle the problem. The answer is no. There are examples of derived categories T = D(R) of rings, and contravariant homological functors C --> Ab which are not restrictions of representables.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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