arXiv subjects
Publications and source records attributed to Francesco Mattiello.
Tilting modules, generalising the notion of progenerator, furnish equivalences between pieces of module categories. This paper is dedicated to study how much these pieces say about the whole category. We will survey the existing results in the literature, introducing also some new insights.
Suppose that $\mathcal{A}$ is an abelian category whose derived category $\mathcal{D}(\mathcal{A})$ has $Hom$ sets and arbitrary (small) coproducts, let $T$ be a (not necessarily classical) ($n$-)tilting object of $\mathcal{A}$ and let $\mathcal{H}$ be the heart of the associated t-structure on $\mathcal{D}(\mathcal{A})$. We show that the inclusion functor $\mathcal{H}\hookrightarrow\mathcal{D}(\mathcal{A})$ extends to a triangulated equivalence of unbounded derived categories $\mathcal{D}(\mathcal{H})\stackrel{\cong}{\longrightarrow}\mathcal{D}(\mathcal{A})$. The result admits a straightforward dualization to cotilting objects in abelian categories whose derived category has $Hom$ sets and arbitrary products.
Let $R$ be a ring and $T \in {\rm Mod-}R$ be a (non-classical) tilting module of finite projective dimension. Let $\mathcal T=({\mathcal T}^{\leq0}, {\mathcal T}^{\geq0})$ be the $t$-structure on $D(R)$ generated by $T$ and ${\mathcal D}=({\mathcal D}^{\leq0}, {\mathcal D}^{\geq0})$ be the natural $t$-structure. We show that the pair $(\mathcal D, \mathcal T)$ is right filterable in the sense of [FMT14], that is, for any $i\in\mathbb Z$ the intersection ${\mathcal D}^{\geq i}\cap {\mathcal T}^{\geq 0}$ is the co-aisle of a $t$-structure. As a consequence, the heart of $\mathcal T$ is derived equivalent to ${\rm Mod-}R$.
Firstly we provide a technique to move torsion pairs in abelian categories via adjoint functors and in particular through Giraud subcategories. We apply this point in order to develop a correspondence between Giraud subcategories of an abelian category $C$ and those of its tilt $H(C)$ i.e., the heart of a t-structure on $D(C)$ induced by a torsion pair.
We give a classification theorem for a relevant class of $t$-structures in triangulated categories, which includes in the case of the derived category of a Grothendieck category, the $t$-structures whose hearts have at most $n$ fixed consecutive non-zero cohomologies. Moreover, by this classification theorem, we deduce the construction of the $t$-tree, a new technique which generalises the filtration induced by a torsion pair. At last we apply our results in the tilting context generalizing the $1$-tilting equivalence proved by Happel, Reiten and Smalø [HRS96]. The last section provides applications to classical $n$-tilting objects, examples of $t$-trees for modules over a path algebra, and new developments on compatible $t$-structures [KeV88b], [Ke07].