In this paper, we study the existence of β₯ -envelopes, -envelopes, β₯ -envelopes, -covers, and -covers where and denote the classes of modules of injective and projective dimension less than or equal to a natural number n, respectively. We prove that over any ring R, special β₯ -preenvelopes and speci
Construction of Modules with Finite Homological Dimensions
β Scribed by Oana Veliche
- Publisher
- Elsevier Science
- Year
- 2002
- Tongue
- English
- Weight
- 163 KB
- Volume
- 250
- Category
- Article
- ISSN
- 0021-8693
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β¦ Synopsis
A new homological dimension, called G * -dimension, is defined for every finitely generated module M over a local noetherian ring R. It is modeled on the CI-dimension of Avramov, Gasharov, and Peeva and has parallel properties. In particular, a ring R is Gorenstein if and only if every finitely generated R-module has finite G * -dimension. The G * -dimension lies between the CI-dimension and the G-dimension of Auslander and Bridger. This relation belongs to a longer sequence of inequalities, where a strict inequality in any place implies equalities to its right and left. Over general local rings, we construct classes of modules that show that a strict inequality can occur at almost every place in the sequence.  2002 Elsevier Science (USA)
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We prove that a Noetherian Hopf algebra of finite global dimension possesses further attractive homological properties, at least when it satisfies a polynomial identity. This applies in particular to quantized enveloping algebras and to quantized function algebras at a root of unity, as well as to c