PreprintCC0arXiv
A note on inverse limits of injective modules
Abstract
Let R be a ring and M a left R-module. We prove that M is an ω1-indexed inverse limit of injective modules with split epimorphic connecting maps, and M is also an ω-indexed inverse limit of a stationary tower defined by a split monic endomorphism of one injective module. These constructions answer two questions of Bergman. We then study the class of direct summands of ω-indexed inverse limit of injective modules with epimorphic connecting maps. Over a commutative Noetherian ring R, they are precisely the Enochs cotorsion modules if and only if gldimR≤1 and SpecR is countable.
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BibTeX
@misc{zhang2026note,
title = {{A note on inverse limits of injective modules}},
author = {Chencheng Zhang},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.36089},
eprint = {2609.36089},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.36089},
note = {CC0},
}
RIS
TY - UNPB
TI - A note on inverse limits of injective modules
AU - Chencheng Zhang
PY - 2026
DA - 2026/09/28
PB - arXiv
DO - 10.48550/arxiv.2609.36089
UR - https://arxiv.org/abs/2609.36089
AB - Let R be a ring and M a left R-module. We prove that M is an ω_1-indexed inverse limit of injective modules with split epimorphic connecting maps, and M is also an ω-indexed inverse limit of a stationary tower defined by a split monic endomorphism of one injective module. These constructions answer two questions of Bergman. We then study the class of direct summands of ω-indexed inverse limit of injective modules with epimorphic connecting maps. Over a commutative Noetherian ring R, they are precisely the Enochs cotorsion modules if and only if gldimR≤1 and SpecR is countable.
ER -