Serre functors and complete torsion pairs

Abstract: Given a torsion pair $(\mathcal{T},\mathcal{F})$ in an abelian category $\mathcal{A}$, there is a t-structure $(\mathcal{U}\mathcal{T},\mathcal{V}\mathcal{T})$ determined by $\mathcal{T}$ on the derived category $D^b(\mathcal{A})$. The existence of derived equivalence between heart $\mathcal{B}$ of the t-structure and $\mathcal{A}$ which naturally extends the embedding $\mathcal{B}\to D^b(\mathcal{A})$ is determined by the completeness of the torsion pair [6]. When $\mathcal{A}$ is the module category of a finite-dimensional hereditary algebra and $\mathcal{U}\mathcal{T}$ is closed under Serre functor, then there exists a triangle equivalence $D^b(\mathcal{B})\to D^b(\mathcal{A})$ [21]. In this case, we give a straightforward proof of the fact torsion pair $(\mathcal{T},\mathcal{F})$ is complete if and only if $\mathcal{U}\mathcal{T}$ is closed under the Serre functor.