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arXiv 2104.08602math.RTmath.CT
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由Gorenstein投射模与λ-纯内射模生成的余挠对

The cotorsion pair generated by the Gorenstein projective modules and $λ$-pure-injective modules

Manuel Cortés-Izurdiaga, Jan Šaroch

AI总结:

本文研究由Gorenstein投射模与λ-纯内射模生成的余挠对,证明其在特定纯内射条件下的完备性,并揭示在0^♯不存在时λ-纯内射性等同于纯内射性,从而刻画右纯半单环。

摘要:

我们证明,若GProj是环R上所有Gorenstein投射模的类,则GP=(GProj,GProj^⊥)是一个余挠对。此外,当所有投射模对某个无穷正则基数λ都是λ-纯内射时(特别地,若R是右Σ-纯内射环),GP是完备的;后一条件被证明与ZFC公理在强紧基数存在性的意义上相一致。我们还对任意无穷正则基数λ的λ-纯内射模进行了深入研究,并在此过程中证明:λ-纯内射模的内射余分解中的任意cosyzygy模都是λ-纯内射的;由一类λ-纯内射模余生成的余挠对可由一个集合余生成,并且在一个额外的技术假设下可由一个集合生成。最后,在集合论假设0^♯不存在的条件下,我们证明右R-模范畴具有足够多的λ-纯内射对象当且仅当环R是右纯半单环。这反过来源于一个相当令人惊讶的结果:在0^♯不存在时,λ-纯内射性等同于纯内射性。

英文摘要:

We prove that, if $\textrm{GProj}$ is the class of all Gorenstein projective modules over a ring $R$, then $\mathfrak{GP}=(\textrm{GProj},\textrm{GProj}^\perp)$ is a cotorsion pair. Moreover, $\mathfrak{GP}$ is complete when all projective modules are $λ$-pure-injective for some infinite regular cardinal $λ$ (in particular, if $R$ is right $Σ$-pure-injective); the latter condition is shown to be consistent with the axioms of ZFC modulo the existence of strongly compact cardinals. We also thoroughly study $λ$-pure-injective modules for an arbitrary infinite regular cardinal $λ$, proving along the way that: any cosyzygy module in an injective coresolution of a $λ$-pure-injective module is $λ$-pure-injective; the cotorsion pair cogenerated by a class of $λ$-pure-injective modules is cogenerated by a set and, under an additional technical assumption, generated by a set. Finally, assuming the set-theoretic hypothesis that $0^\sharp$ does not exist, we prove that the category of right $R$-modules has enough $λ$-pure-injective objects if and only if the ring $R$ is right pure-semisimple. This, in turn, follows from a rather surprising result that $λ$-pure-injectivity amounts to pure-injectivity in the absence of $0^\sharp$.

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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