arXiv subjects

Fatemeh Mohammadi Aghjeh Mashhad

Publications and source records attributed to Fatemeh Mohammadi Aghjeh Mashhad.

4 recordsLinked to original sources

arXiv2019

On the New Intersection Theorem for totally reflexive modules

Let (R,m,k) be a local ring. We establish a totally reflexive analogue of the New Intersection Theorem, provided for every totally reflexive R-module M, there is a big Cohen-Macaulay R-module B_M such that the socle of B_M\otimes_RM is zero. When R is a quasi-specialization of a G-regular local ring or when M has complete intersection dimension zero, we show the existence of such a big Cohen-Macaulay R-module. It is conjectured that if R admits a non-zero Cohen-Macaulay module of finite Gorenstein dimension, then it is Cohen-Macaulay. We prove this conjecture if either R is a quasi-specialization of a G-regular local ring or a quasi-Buchsbaum local ring.

math.AC↗

arXiv2012

On the existence of certain modules of finite Gorenstein homological dimensions

Let (R,m) be a commutative Noetherian local ring. It is known that R is Cohen-Macaulay if there exists either a nonzero finitely generated R-module of finite injective dimension or a nonzero Cohen-Macaulay R-module of finite projective dimension. In this paper, we investigate the Gorenstein analogues of these facts.

math.AC↗

arXiv2012

Local homology and Gorenstein flat modules

Let $R$ be a commutative Noetherian ring, $\fa$ an ideal of $R$ and $\mathcal{D}(R)$ denote the derived category of $R$-modules. We investigate the theory of local homology in conjunction with Gorenstein flat modules. Let $X$ be a homologically bounded to the right complex and $Q$ a bounded to the right complex of Gorenstein flat $R$-modules such that $Q$ and $X$ are isomorphic in $\mathcal{D}(R)$. We establish a natural isomorphism ${\bf L}Λ^{\fa}(X)\simeq Λ^{\fa}(Q)$ in $\mathcal{D}(R)$ which immediately asserts that $\sup {\bf L}Λ^{\fa}(X)\leq \Gfd_RX$. This isomorphism yields several consequences. For instance, in the case $R$ possesses a dualizing complex, we show that $\Gfd_R {\bf L}Λ^{\fa}(X)\leq \Gfd_RX$. Also, we establish a criterion for regularity of Gorenstein local rings.

math.AC↗

arXiv2012

Foxby equivalence, local duality and Gorenstein homological dimensions

Let $(R,\fm)$ be a local ring and $(-)^{\vee}$ denote the Matlis duality functor. We investigate the relationship between Foxby equivalence and local duality through generalized local cohomology modules. Assume that $R$ possesses a normalized dualizing complex $D$ and $X$ and $Y$ are two homologically bounded complexes of $R$-modules with finitely generated homology modules. We present several duality results for $\fm$-section complex ${\bf R}Γ_{\fm}({\bf R}\Hom_R(X,Y))$. In particular, if G-dimension of $X$ and injective dimension of $Y$ are finite, then we show that $${\bf R}Γ_{\fm}({\bf R}\Hom_R(X,Y))\simeq ({\bf R}\Hom_R(Y,D\otimes_ R^{\bf L}X))^{\vee}.$$ We deduce several applications of these duality results. In particular, we establish Grothendieck's non-vanishing Theorem in the context of generalized local cohomology modules.

math.AC↗