Tower
Tower
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DOI:
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发表时间:
2017
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通讯作者:
G. Wrenn
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文献类型:
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作者:
G. Wrenn
In this paper, the author defines and investigates a left relative separable tower of rings. It is shown that a progenerator extension has right depth 2 if and only if the ring extension together with its right endomorphism ring is a left relative H-separable tower. This result applies to twisted or ordinary Frobenius extensions with a surjective Frobenius homomorphism. Thereby, normality for Hopf subalgebras of finite dimensional Hopf algebras is characterized via this tower condition.