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Related papers: On the composition of two spherical twists

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For a flat morphism $\pi \colon X \to T$ between smooth quasi-projective varieties and its fiber $X_0$, we prove that spherical objects on $D^b(X)$ pushed-forward from $D^b(X_0)$ induce autoequivalences of $D^b(X_0)$ itself. Our…

Algebraic Geometry · Mathematics 2025-05-26 Hayato Arai

Given a categorical dynamical system, i.e. a triangulated category together with an endofunctor, one can try to understand the complexity of the system by computing the entropy of the endofunctor. Computing the entropy of the composition of…

Algebraic Geometry · Mathematics 2021-07-14 Federico Barbacovi , Jongmyeong Kim

We study the relationship between the categorical entropy of the twist and cotwist functors along a spherical functor. In particular, we prove the categorical entropy of the twist functor coincides with that of the cotwist functor if the…

Algebraic Geometry · Mathematics 2022-09-15 Jongmyeong Kim

We describe all groups that can be generated by two twists along spherical sequences in an enhanced triangulated category. It will be shown that with one exception such a group is isomorphic to an abelian group generated by not more than…

Representation Theory · Mathematics 2019-11-28 Yury Volkov

We investigate the triangulated structure of stable monomorphism categories (filtered chain categories) over a Frobenius category. The high degree of symmetry of linear quivers leads to a plethora of semiorthogonal decompositions into…

Category Theory · Mathematics 2026-04-27 Jonas Frank , Mathias Schulze

We describe in terms of spherical twists the Serre functors of many interesting semiorthogonal components, called residual categories, of the derived categories of projective varieties. In particular, we show the residual categories of Fano…

Algebraic Geometry · Mathematics 2022-01-03 Alexander Kuznetsov , Alexander Perry

Let C be a triangulated category with a Serre functor S and X a non-zero contravariantly finite rigid subcategory of C. Then X is cluster tilting if and only if the quotient category C/X is abelian and S(X)=X[2]. As an application, this…

Representation Theory · Mathematics 2020-03-27 Panyue Zhou

For every adjunction of stable $\infty$-categories -- or more generally, in any locally stable $(\infty,2)$-category -- we give a simple procedure for inverting the twist and cotwist functors associated to this adjunction. As a consequence,…

Category Theory · Mathematics 2026-05-15 Fernando Abellán , Jonte Gödicke

This paper concerns spherical adjunctions of stable $\infty$-categories and their relation to monadic adjunctions. We begin with a proof of the 2/4 property of spherical adjunctions in the setting of stable $\infty$-categories. The proof is…

Algebraic Topology · Mathematics 2022-08-02 Merlin Christ

The purpose of this short note is to study Serre functors of categories of quasicoherent sheaves on stacks of the form $\mathcal{Y} = \mathrm{Spec} A/G$ where $G$ is a reductive group acting on $\mathrm{Spec} A$ with a unique closed orbit.…

Algebraic Geometry · Mathematics 2026-05-25 Ivan Noden

We provide a categorical interpretation of a well-known identity from linear algebra as an isomorphism of certain functors between triangulated categories arising from finite dimensional algebras. As a consequence, we deduce that the Serre…

Representation Theory · Mathematics 2019-03-12 Sefi Ladkani

We show that the autoequivalence group of the derived category of any smooth projective toric surface is generated by the standard equivalences and spherical twists obtained from -2-curves. In many cases we give all relations between these…

Algebraic Geometry · Mathematics 2015-03-17 Nathan Broomhead , David Ploog

Given a torsion pair $(\mathcal{T},\mathcal{F})$ in an abelian category $\mathcal{A}$ and its Happel-Reiten-Smal{\o} tilt $\mathcal{B}$, the equivalence of the realization functor $D^b({\mathcal B})\to D^b({\mathcal A})$ is determined by…

Representation Theory · Mathematics 2025-10-24 Zhe Han , Ping He

We prove that the full twist is a Serre functor in the homotopy category of type A Soergel bimodules. As a consequence, we relate the top and bottom Hochschild degrees in Khovanov-Rozansky homology, categorifying a theorem of K\'alm\'an.

Representation Theory · Mathematics 2020-03-19 Eugene Gorsky , Matthew Hogancamp , Anton Mellit , Keita Nakagane

We develop the theory of semi-orthogonal decompositions and spherical functors in the framework of stable $\infty$-categories. Building on this, we study the relative Waldhausen S-construction $S_\bullet(F)$ of a spherical functor $F$ and…

Algebraic Geometry · Mathematics 2021-06-08 Tobias Dyckerhoff , Mikhail Kapranov , Vadim Schechtman , Yan Soibelman

Let E be a Frobenius category, let_E_ denote its stable category. The shift functor on_E_ induces a first shift functor on the category of acyclic complexes with entries in_E_ by pointwise application. Shifting a complex by 3 positions…

Category Theory · Mathematics 2010-09-14 Matthias Kuenzer

We study sets of commuting reflection functors in the derived category of sheaves on Calabi-Yau varieties. We show that such a collection is determined by a set of mutually orthogonal spherical objects. We also show that when the spherical…

Algebraic Geometry · Mathematics 2012-06-27 Antony Maciocia

We show that the inverse Serre functor for the constructible derived category $\mathbf{D}^\mathrm{b}_\mathrm{c}(\mathbb{P}^n)$ is given by the $\mathbb{P}$-twist at the simple perverse sheaf corresponding to the open stratum. Moreover, we…

Representation Theory · Mathematics 2025-06-09 Lukas Bonfert , Alessio Cipriani

On a smooth projective threefold, we construct an essentially surjective functor $\mathcal{F}$ from a category of two-term complexes to a category of quotients of coherent sheaves, and describe the fibers of this functor. Under a coprime…

Algebraic Geometry · Mathematics 2023-02-22 Jason Lo

Every simple quadrangulation of the sphere is generated by a graph called a pseudo-double wheel with two local expansions (Brinkmann et al. "Generation of simple quadrangulations of the sphere." Discrete Math., Vol. 305, No. 1-3, pp. 33-54,…

Metric Geometry · Mathematics 2012-10-08 Yohji Akama