No Arabic abstract
Let $R$ be a commutative ring. We show that any complete duality pair gives rise to a theory of relative homological algebra, analogous to Gorenstein homological algebra. Indeed Gorenstein homological algebra over a commutative Noetherian ring of finite Krull dimension can be recovered from the duality pair $(mathcal{F},mathcal{I})$ where $mathcal{F}$ is the class of flat $R$-modules and $mathcal{I}$ is the class of injective $R$-modules. For a general $R$, the AC-Gorenstein homological algebra of Bravo-Gillespie-Hovey is the one coming from the duality pair $(mathcal{L},mathcal{A})$ where $mathcal{L}$ is the class of level $R$-modules and $mathcal{A}$ is class of absolutely clean $R$-modules. Indeed we show here that the work of Bravo-Gillespie-Hovey can be extended to obtain similar abelian model structures on $R$-Mod from any a complete duality pair $(mathcal{L},mathcal{A})$. It applies in particular to the original duality pairs constructed by Holm-J{o} rgensen.
We introduce what is meant by an AC-Gorenstein ring. It is a generalized notion of Gorenstein ring which is compatible with the Gorenstein AC-injective and Gorenstein AC-projective modules of Bravo-Gillespie-Hovey. It is also compatible with the notion of $n$-coherent rings introduced by Bravo-Perez: So a $0$-coherent AC-Gorenstein ring is precisely a usual Gorenstein ring in the sense of Iwanaga, while a $1$-coherent AC-Gorenstein ring is precisely a Ding-Chen ring. We show that any AC-Gorenstein ring admits a stable module category that is compactly generated and is the homotopy category of two Quillen equivalent abelian model category structures. One is projective with cofibrant objects the Gorenstein AC-projective modules while the other is an injective model structure with fibrant objects the Gorenstein AC-injectives.
We introduce a new definition of a generalized logarithmic module of multiarrangements by uniting those of the logarithmic derivation and the differential modules. This module is realized as a logarithmic derivation module of an arrangement of hyperplanes with a multiplicity consisting of both positive and negative integers. We consider several properties of this module including Saitos criterion and reflexivity. As applications, we prove a shift isomorphism and duality of some Coxeter multiarrangements by using the primitive derivation.
Let R be a commutative Noetherian ring. We introduce the notion of colocalization functors with supports in arbitrary subsets of Spec R, which is a natural generalization of right derived functors of section functors with supports in specialization-closed subsets. We prove that the local duality theorem and the vanishing theorem of Grothendieck type hold for colocalization functors.
We will define the Alexander duality for strongly stable ideals. More precisely, for a strongly stable ideal $I subset Bbbk[x_1, ldots, x_n]$ with ${rm deg}(mathsf{m}) le d$ for all $mathsf{m} in G(I)$, its dual $I^* subset Bbbk[y_1, ldots, y_d]$ is a strongly stable ideal with ${rm deg}(mathsf{m}) le n$ for all $mathsf{m} in G(I^*)$. This duality has been constructed by Fl$o$ystad et al. in a different manner, so we emphasis applications here. For example, we will describe the Hilbert serieses of the local cohomologies $H_mathfrak{m}^i(S/I)$ using the irreducible decomposition of $I$ (through the Betti numbers of $I^*$).
We prove a duality theorem for certain graded algebras and show by various examples different kinds of failure of tameness of local cohomology.