Ghost-tilting objects in triangulated categories

Research paper by Wuzhong Yang, Bin Zhu

Indexed on: 31 Mar '15Published on: 31 Mar '15Published in: Mathematics - Representation Theory


Assume that $\mathcal{D}$ is a Krull-Schmidt, Hom-finite triangulated category with a Serre functor and a cluster-tilting object $T$. We introduce the notion of ghost-tilting objects, and $T[1]$-tilting objects in $\mathcal{D}$, which are a generalization of cluster-tilting objects. When $\mathcal{D}$ is $2$-Calabi-Yau, the ghost-tilting objects are cluster-tilting. Let $\Lambda={\rm End}^{op}_{\mathcal{D}}(T)$ be the endomorphism algebra of $T$. We show that there exists a bijection between $T[1]$-tilting objects in $\mathcal{D}$ and support $\tau$-tilting $\Lambda$-modules, which generalizes a result of Adachi-Iyama-Reiten [AIR]. We develop a basic theory on $T[1]$-tilting objects. In particular, we introduce a partial order on the set of $T[1]$-tilting objects and mutation of $T[1]$-tilting objects, which can be regarded as a generalization of `cluster-tilting mutation'. As an application, we give a partial answer to a question posed in [AIR].