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David Pauksztello

Publications and source records attributed to David Pauksztello.

At least 19 recordsLinked to original sources
arXiv2026

Simple tilts of length hearts and simple-minded mutation

We characterise when a simple Happel-Reiten-Smalo tilt of a length heart is again a length heart in terms of approximation theory and the existence of a stability condition with a phase gap. We apply simple-minded reduction to provide a sufficient condition for infinite iterability of simple-minded mutation/simple tilting. We use simple-minded mutation pairs to provide a common framework to show that mutation of simple-minded collections (resp. $w$-simple-minded systems, for $w \geq 1$) gives simple-minded collections (resp. $w$-simple-minded systems) under mild conditions, in the process providing a unified proof of results of Alex Dugas and Peter Jorgensen. Finally, we show that under mild conditions, mutation of simple-minded collections is compatible with mutation of $w$-simple-minded systems via a singularity category construction due to Haibo Jin.

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arXiv2026

Partial compactification of stability manifolds via massless semistable objects

We introduce two extensions of the space of Bridgeland stability conditions of a triangulated category. First we consider lax stability conditions where semistable objects are allowed to have mass zero but still have a phase. The subcategory of massless objects is thick and there is an induced Bridgeland stability on the quotient category. We study deformations of lax stability conditions. Second we consider the space arising by identifying lax stability conditions which are deformation-equivalent with fixed charge. This second space is stratified by stability spaces of Verdier quotients of the triangulated category by thick subcategories of massless objects. We illustrate our results through examples in which the Grothendieck group has rank $2$. For these, our extended stability spaces can be explicitly described and related to the wall-and-chamber structure of the stability space.

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arXiv2026

Fishing for complements

Given a presilting object in a triangulated category, we find necessary and sufficient conditions for the existence of a complement. This is done both for classic (pre)silting objects and for large (pre)silting objects. The key technique is the study of associated co-t-structures. As a consequence of our techniques we recover some known cases of the existence of complements, including for derived categories of some hereditary abelian categories and for silting-discrete algebras. Moreover, we also show that a finite-dimensional algebra is silting discrete if and only if every bounded large silting complex is equivalent to a compact one.

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arXiv2024

The heart fan of an abelian category

We apply convex geometry (cones, fans) to homological input (abelian categories, hearts of bounded t-structures) to construct a new invariant of an abelian category, its heart fan. This can be viewed as a `universal phase diagram' for Bridgeland stability conditions with the given heart. When the abelian category is the module category of a finite-dimensional algebra, the heart fan is complete and contains the g-fan as the subfan of full-dimensional cones. The heart fan is also closely related to the wall-and-chamber structure for King semistability.

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arXiv2021

Functorially finite hearts, simple-minded systems in negative cluster categories, and noncrossing partitions

Let $Q$ be an acyclic quiver and $w \geq 1$ be an integer. Let $\mathsf{C}_{-w} (\mathbf{k} Q)$ be the $(-w)$-cluster category of $\mathbf{k} Q$. We show that there is a bijection between simple-minded collections in $\mathsf{D}^b (\mathbf{k} Q)$ lying in a fundamental domain of $\mathsf{C}_{-w} (\mathbf{k} Q)$ and $w$-simple-minded systems in $\mathsf{C}_{-w} (\mathbf{k} Q)$. This generalises the same result of Iyama-Jin in the case that $Q$ is Dynkin. A key step in our proof is the observation that the heart $\mathsf{H}$ of a bounded t-structure in a Hom-finite, Krull-Schmidt, $\mathbf{k}$-linear saturated triangulated category $\mathsf{D}$ is functorially finite in $\mathsf{D}$ if and only if $\mathsf{H}$ has enough injectives and enough projectives. We then establish a bijection between $w$-simple-minded systems in $\mathsf{C}_{-w} (\mathbf{k} Q)$ and positive $w$-noncrossing partitions of the corresponding Weyl group $W_Q$.

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arXiv2020

Co-t-structures, cotilting and cotorsion pairs

Let $\mathsf{T}$ be a triangulated category with shift functor $Σ\colon \mathsf{T} \to \mathsf{T}$. Suppose $(\mathsf{A},\mathsf{B})$ is a co-t-structure with coheart $\mathsf{S} = Σ\mathsf{A} \cap \mathsf{B}$ and extended coheart $\mathsf{C} = Σ^2 \mathsf{A} \cap \mathsf{B} = \mathsf{S} * Σ\mathsf{S}$, which is an extriangulated category. We show that there is a bijection between co-t-structures $(\mathsf{A}',\mathsf{B}')$ in $\mathsf{T}$ such that $\mathsf{A} \subseteq \mathsf{A}' \subseteq Σ\mathsf{A}$ and complete cotorsion pairs in the extended coheart $\mathsf{C}$. In the case that $\mathsf{T}$ is Hom-finite, $\mathbf{k}$-linear and Krull-Schmidt, we show further that there is a bijection between complete cotorsion pairs in $\mathsf{C}$ and functorially finite torsion pairs in $\mathsf{mod}\, \mathsf{S}$.

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arXiv2020

On extensions for gentle algebras

We give a complete description of a basis of the extension spaces between indecomposable string and quasi-simple band modules in the module category of a gentle algebra.

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arXiv2020

Addendum and Erratum: Mapping cones for morphisms involving a band complex in the bounded derived category of a gentle algebra

In this note we correct two oversights in [Mapping cones in the bounded derived category of a gentle algebra, J. Algebra 530 (2019), 163--194, also arXiv:1609.09688] which only occur when a band complex is involved. As a consequence we see that the mapping cone of a morphism between two band complexes can decompose into arbitrarily many indecomposable direct summands.

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arXiv2018

Simple-minded systems and reduction for negative Calabi-Yau triangulated categories

We develop the basic properties of $w$-simple-minded systems in $(-w)$-Calabi-Yau triangulated categories for $w \geq 1$. The main result is a reduction technique for negative Calabi-Yau triangulated categories. We show that the theory of simple-minded systems exhibits striking parallels with that of cluster-tilting objects. Our construction provides an inductive technique for constructing simple-minded systems.

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arXiv2018

Discrete triangulated categories

We introduce and study several homological notions which generalise the discrete derived categories of D. Vossieck. As an application, we show that Vossieck discrete algebras have this property with respect to all bounded t-structures. We give many examples of triangulated categories regarding these notions.

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arXiv2017

Contractibility of the stability manifold for silting-discrete algebras

We show that any bounded t-structure in the bounded derived category of a silting-discrete algebra is algebraic, i.e. has a length heart with finitely many simple objects. As a corollary, we obtain that the space of Bridgeland stability conditions for a silting-discrete algebra is contractible.

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arXiv2016

The Ziegler spectrum for derived-discrete algebras

Let $Λ$ be a derived-discrete algebra. We show that the Krull-Gabriel dimension of the homotopy category of projective $Λ$-modules, and therefore the Cantor-Bendixson rank of its Ziegler spectrum, is $2$, thus extending a result of Bobiński and Krause. We also describe all the indecomposable pure-injective complexes and hence the Ziegler spectrum for derived-discrete algebras, extending a result of Z. Han. Using this, we are able to prove that all indecomposable complexes in the homotopy category of projective $Λ$-modules are pure-injective, so obtaining a class of algebras for which every indecomposable complex is pure-injective but which are not derived pure-semisimple.

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arXiv2015

Discrete derived categories II: The silting pairs CW complex and the stability manifold

Discrete derived categories were studied initially by Vossieck \cite{Vossieck} and later by Bobiński, Geiß, Skowroński \cite{BGS}. In this article, we define the CW complex of silting pairs for a triangulated category and show that it is contractible in the case of discrete derived categories. We provide an explicit embedding from the silting CW complex into the stability manifold. By work of Qiu and Woolf, there is a deformation retract of the stability manifold onto the silting pairs CW complex. We obtain that the space of stability conditions of discrete derived categories is contractible.

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arXiv2015

Torsion pairs in a triangulated category generated by a spherical object

We extend Ng's characterisation of torsion pairs in the 2-Calabi-Yau triangulated category generated by a 2-spherical object to the characterisation of torsion pairs in the w-Calabi-Yau triangulated category, $T_w$, generated by a w-spherical object for any integer w. Inspired by the combinatorics of $T_w$ for w < 0, we also characterise the torsion pairs in a certain w-Calabi-Yau orbit category of the bounded derived category of the path algebra of Dynkin type A.

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arXiv2013

Classification of co-slicings and co-t-structures for the Kronecker algebra

In this paper we introduce the notion of a 'generalised' co-slicing of a triangulated category. This generalises the theory of co-stability conditions in a manner analogous to the way in which Gorodentsev, Kuleshov and Rudakov's t-stabilities generalise Bridgeland's theory of stability conditions. As an application of this notion, we use a complete classification of 'generalised' co-slicings in the bounded derived category of the Kronecker algebra, $D^b(KQ)$, to obtain a classification of co-t-structures in $D^b(Q)$. This is then used to compute the co-stability manifold of $D^b(KQ)$.

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