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A topological version of the famous Hedetniemi conjecture says: The mapping index of the Cartesian product of two $\mathbb Z/2$-spaces is equal to the minimum of their $\mathbb Z/2$-indexes. The main purpose of this article is to study the…

Combinatorics · Mathematics 2025-07-15 Vuong Bui , Hamid Reza Daneshpajouh

For any two degrees coprime to the rank, we construct a family of ring isomorphisms parameterized by GSp(2g) between the cohomology of the moduli spaces of stable Higgs bundles which preserve the perverse filtrations. As consequences, we…

Algebraic Geometry · Mathematics 2021-12-15 Mark Andrea de Cataldo , Davesh Maulik , Junliang Shen , Siqing Zhang

We show that the homology of strata of abelian differentials stabilizes in a range where the number of simple zeros is large relative to the homological degree. In this range, we show that the rational cohomology agrees with the restriction…

Algebraic Geometry · Mathematics 2026-03-26 Philip Tosteson

A well-known and old result of Hazewinkel and Koszul states that the cohomology of a finite-dimensional Lie algebra is isomorphic, up to a suitable shift, to its twisted homology, a Lie-theoretical version of Poincare duality. This paper…

Quantum Algebra · Mathematics 2026-01-26 Andrey Lazarev , Rong Tang

Let $L$ be a simply-connected simple connected algebraic group over a number field $F$, and $H$ be a semisimple absolutely maximal connected $F$-subgroup of $L$. Under a cohomological condition, we prove an asymptotic formula for the number…

Number Theory · Mathematics 2021-11-25 Pengyu Yang

We prove the toral rank conjecture of Halperin in some new cases. Our results apply to certain elliptic spaces that have a two-stage Sullivan minimal model, and are obtained by combining new lower bounds for the dimension of the cohomology…

Algebraic Topology · Mathematics 2009-11-10 Barry Jessup , Gregory Lupton

We present a development of cellular cohomology in homotopy type theory. Cohomology associates to each space a sequence of abelian groups capturing part of its structure, and has the advantage over homotopy groups in that these abelian…

Logic in Computer Science · Computer Science 2023-06-22 Ulrik Buchholtz , Kuen-Bang Hou

We prove the Burghelea Conjecture for groups satisfying some additional cohomological property.

K-Theory and Homology · Mathematics 2017-03-23 Alexander Dranishnikov

The cohomological dimension of a field is the largest degree with non-vanishing Galois cohomology. Serre's "Conjecture II" predicts that for every perfect field of cohomological dimension $2$, every torsor over the field for a semisimple,…

Algebraic Geometry · Mathematics 2017-04-11 Jason Michael Starr

The Lichtenbaum-Quillen conjecture for smooth complex varieties states that algebraic and topological K-theory with finite coefficients become isomorphic in high degrees. We define the "Lichtenbaum-Quillen dimension" of a variety in terms…

Algebraic Geometry · Mathematics 2026-04-14 Nicolas Addington , Elden Elmanto

We prove the Morrison-Kawamata cone conjecture for klt Calabi-Yau pairs in dimension 2. That is, for a large class of rational surfaces as well as K3 surfaces and abelian surfaces, the action of the automorphism group of the surface on the…

Algebraic Geometry · Mathematics 2019-12-19 Burt Totaro

We demonstrate that companionships and conjunctions in double $\infty$-categories -- and more generally, in double Segal spaces -- extend to functors out of the free-living companionship and conjunction respectively. Specifically, we prove…

Category Theory · Mathematics 2025-04-09 Jaco Ruit

For a semisimple complex algebraic group $G$ we determine the rational cohomology and the Hodge-Tate structure of the moduli stack ${\mathscr B}un_{G,X}$ of principal $G$-bundles over a connected smooth complex projective variety $X$ of…

Algebraic Geometry · Mathematics 2025-08-06 Pedro L. del Angel R. , Frank Neumann

We prove that in a stable range, the rational cohomology of the moduli space of curves with level structures is the same as that of the ordinary moduli space of curves.

Algebraic Geometry · Mathematics 2025-06-25 Andrew Putman

We prove a result that enables us to calculate the rational homotopy of a wide class of spaces by the theory of minimal models.

Algebraic Topology · Mathematics 2023-12-12 Christoph Bock

If two conical symplectic resolutions $X\to X_0$ and $X^!\to X_0^!$ are symplectic dual, the cohomology ring $H^*(X)$ and the coordinate ring of $\mathbb{C}^*$-fixed points in $X_0^!$ are expected to be isomorphic as graded algebras. This…

Algebraic Geometry · Mathematics 2021-10-06 Kohei Hatano

The original Smale Conjecture asserted that the inclusion of the group O(4) of isometries of the round 3-sphere S into the full diffeomorphism group Diff(S) is a homotopy equivalence. The (Generalized) Smale Conjecture asserts that the…

Geometric Topology · Mathematics 2007-05-23 Sungbok Hong , Darryl McCullough , J. Hyam Rubinstein

In this paper we look at the notion of cohomological triviality of fibrations of homogeneous spaces of affine algebraic groups defined over $\mathbb{C}$ and use topological methods, primarily the theory of covering spaces. This is made…

Algebraic Geometry · Mathematics 2018-12-27 A. J. Parameswaran , Amith Shastri K

This note extends Quillen's Theorem A to a large class of categories internal to topological spaces. This allows us to show that under a mild condition a fully faithful and essentially surjective functor between such topological categories…

Algebraic Topology · Mathematics 2024-06-12 David Michael Roberts

We produce a criterion for open sets in projective $n$-space over a separably closed field to have \'etale cohomological dimension bounded by $2n-3$. We use the criterion to exhibit a scheme for which \'etale cohomological dimension is…

Commutative Algebra · Mathematics 2010-12-01 Manoj Kummini , Uli Walther