vSpela vSpenko

collaborators

6 papers

math.AG2026

Perverse schobers and GKZ systems

Å pela Å penko, Michel Van den Bergh

Perverse schobers are categorifications of perverse sheaves. In prior work we constructed a perverse schober on a partial compactification of the stringy KÃ¤hler moduli space (SKMS…

math.CO2026

Catalan numbers, parking functions, permutahedra and noncommutative Hilbert schemes

Valery Lunts, Å pela Å penko, Michel Van den Bergh

We find an explicit $S_{n}$ -equivariant bijection between the integral points in a certain zonotope in $R^{n}$ , combinatorially equivalent to the permutahedron, and the set of…

math.AG2026

On the GKZ discriminant locus

Å pela Å penko, Michel Van den Bergh

Let $A$ be an integral matrix and let $P$ be the convex hull of its columns. By a result of Gelfand, Kapranov and Zelevinski, the so-called principal $A$ -determinant locus is equal…

math.RT2025

An equivalence linking CM-types $A_{\infty}$ and $D_{\infty}$

Charley Cummings, Sira Gratz, Ellen Kirkman +3

We show that, for a specific grading, the stable categories of graded maximal Cohen-Macaulay modules over hypersurfaces of type $A_{\infty}$ and $D_{\infty}$ are equivalent.

math.KT2025

Comparison of Cohomological and K-theoretical Hall algebra

Felix KÃ¼ng, Å pela Å penko

We give a more conceptual construction of a comparison algebra morphism from the K-theoretical Hall algebra to a twist of the cohomological Hall algebra associated to a symmetric q…

math.RT2025

Additive diameters of group representations

Urban Jezernik, Å pela Å penko

We explore the concept of additive diameters in the context of group representations, unifying various noncommutative Waring-type problems. Given a finite-dimensional representatio…