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Stably semiorthogonally indecomposable varieties
Épijournal de Géométrie Algébrique. 2023. Vol. 7. Article 7700.
Pirozhkov Dmitrii
A triangulated category is said to be indecomposable if it admits no nontrivial semiorthogonal decompositions. We introduce a definition of a noncommutatively stably semiorthogonally indecomposable (NSSI) variety. This propery implies, among other things, that each smooth proper subvariety has indecomposable derived category of coherent sheaves, and that if Y is NSSI, then for any variety X all semiorthogonal decompositions of X×Y are induced from decompositions of X. We prove that any variety whose Albanese morphism is finite is NSSI, and that the total space of a fibration over NSSI base with NSSI fibers is also NSSI. We apply this indecomposability to deduce that there are no phantom subcategories in some varieties, including surfaces C×P1, where C is any smooth proper curve of positive genus.
Vasilev D., / Series arXiv "math". 2025.
Added: October 14, 2025
Pirozhkov Dmitrii, European Journal of Mathematics 2023 Vol. 9 No. 2 Article 45
Raphaël Rouquier introduced an invariant of triangulated categories which is known as Rouquier dimension. Orlov conjectured that for any smooth quasi-projective variety X the Rouquier dimension of 𝐷bcoh(𝑋) is equal to dim𝑋. In this note we show that some blow-ups of projective spaces satisfy Orlov’s conjecture. This includes a blow-up of ℙ2 in nine arbitrary ...
Added: September 29, 2023
Pirozhkov Dmitrii, Advances in Mathematics 2023 Vol. 424 Article 109046
We study admissible subcategories of derived categories of coherent sheaves on del Pezzo surfaces and rational elliptic surfaces. Using a relation between admissible subcategories and anticanonical divisors we prove the following results. First, we classify all admissible subcategories of the projective plane by showing that each is generated by a subcollection of a full exceptional ...
Added: September 29, 2023
Pirozhkov Dmitrii, International Mathematics Research Notices 2022 No. 3 P. 2250–2273
Let U be the tautological subbundle on the Grassmannian Gr(k,n). There is a natural morphism Tot(U)→An. Using it, we give a semiorthogonal decomposition for the bounded derived category Dbcoh(Tot(U)) into several exceptional objects and several copies of Dbcoh(An). We also prove a global version of this result: given a vector bundle E with a regular ...
Added: September 29, 2023
Shinder E., Kuznetsov A., Karmazyn J., Journal of the European Mathematical Society 2022 Vol. 24 No. 2 P. 461–526
We develop an approach that allows one to construct semiorthogonal decompositions of
derived categories of surfaces with cyclic quotient singularities whose components are equivalent
to derived categories of local finite-dimensional algebras.
We first explain how to induce a semiorthogonal decomposition of a surface X with rational
singularities from a semiorthogonal decomposition of its resolution. In the case when X ...
Added: November 24, 2022
Bergh D., Gorchinskiy S., Larsen M. et al., Journal of Algebraic Geometry 2021 Vol. 30 P. 685–757
Given a variety with a finite group action, we compare its equivariant categorical measure, that is, the categorical measure of the corresponding quotient stack, and the categorical measure of the extended quotient. Using weak factorization for orbifolds, we show that for a wide range of cases that these two measures coincide. This implies, in particular, ...
Added: November 17, 2021
Galkin S., Belmans P., Mukhopadhyay S., / Series math "arxiv.org". 2020. No. 2009.05568.
We introduce graph potentials, which are Laurent polynomials associated to (colored) trivalent graphs. These graphs encode degenerations of curves to rational curves, and graph potentials encode degenerations of the moduli space of rank 2 bundles with fixed determinant. We show that the birational type of the graph potential only depends on the homotopy type of ...
Added: April 15, 2021
Pirozhkov D., / Series arXiv "math". 2018.
Let U be the tautological subbundle on the Grassmannian Gr(k,n). There is a natural morphism Tot(U)→𝔸^n. Using it, we give a semiorthogonal decomposition for the bounded derived category D^b_coh(Tot(U)) into several exceptional objects and several copies of D^b_coh(𝔸n). We also prove a global version of this result: given a vector bundle E with a regular section s, consider a subvariety of the ...
Added: December 6, 2018
Kuznetsov A., Perry A., Compositio Mathematica 2018 Vol. 154 No. 7 P. 1362–1406
We study the derived categories of coherent sheaves on Gushel–Mukai varieties. In the derived category of such a variety, we isolate a special semiorthogonal component, which is a K3 or Enriques category according to whether the dimension of the variety is even or odd. We analyze the basic properties of this category using Hochschild homology, ...
Added: September 13, 2018
Anton Fonarev, / Series arXiv "math". 2018.
We construct a mininal Lefschetz decomposition of the bounded derived category of coherent sheaves on the isotropic Grassmannian $\IGr(3,7)$. Moreover, we show that $\IGr(3, 7)$ admits a full exceptional collection consisting of equivariant vector bundles. ...
Added: April 20, 2018
Fonarev A., Kuznetsov A., Journal of London Mathematical Society 2018 Vol. 97 No. 2 P. 24–46
We prove that the derived category D(C) of a generic curve of genus greater than one embeds into the derived category D(M) of the moduli space M of rank two stable bundles on C with fixed determinant of odd degree. ...
Added: November 7, 2017
Bodzenta A., Bondal A. I., / Series arXiv "math". 2017.
Given a relatively projective birational morphism f:X→Y of smooth algebraic spaces with dimension of fibers bounded by 1, we construct tilting relative (over Y) generators TX,f and SX,f in Db(X). We develop a piece of general theory of strict admissible lattice filtrations in triangulated categories and show that Db(X) has such a filtration L where ...
Added: August 28, 2017
Polishchuk A., van der Bergh M., Journal of the European Mathematical Society 2019 Vol. 21 No. 9 P. 2653–2749
We consider the derived category of coherent sheaves on a complex vector space equivariant with respect to an action of a finite reflection group G. In some cases, including Weyl groups of type A, B, G_2, F_4, as well as the groups G(m,1,n), we construct a semiorthogonal decomposition of this category, indexed by the conjugacy ...
Added: August 22, 2017