Tautological and non-tautological cycles on the moduli space of abelian varieties

S Canning, D Oprea, R Pandharipande - arXiv preprint arXiv:2408.08718, 2024 - arxiv.org
The tautological Chow ring of the moduli space $\mathcal {A} _g $ of principally polarized
abelian varieties of dimension $ g $ was defined and calculated by van der Geer in 1999. By …

A presentation of symplectic Steinberg modules and cohomology of

B Brück, P Patzt, RJ Sroka - arXiv preprint arXiv:2306.03180, 2023 - arxiv.org
Borel-Serre proved that the integral symplectic group $\operatorname {Sp} _ {2n}(\mathbb
{Z}) $ is a virtual duality group of dimension $ n^ 2$ and that the symplectic Steinberg …

Divisors and curves on logarithmic mapping spaces

P Kennedy-Hunt, N Nabijou, Q Shafi, W Zheng - Selecta Mathematica, 2024 - Springer
We determine the rational class and Picard groups of the moduli space of stable logarithmic
maps in genus zero, with target projective space relative a hyperplane. For the class group …

On the weight zero compactly supported cohomology of

M Brandt, M Chan, S Kannan - arXiv preprint arXiv:2307.01819, 2023 - arxiv.org
For $ g\ge 2$ and $ n\ge 0$, let $\mathcal {H} _ {g, n}\subset\mathcal {M} _ {g, n} $ denote
the complex moduli stack of $ n $-marked smooth hyperelliptic curves of genus $ g $. A …

Unstable cohomology of and the odd commutative graph complex

F Brown, S Hu, E Panzer - arXiv preprint arXiv:2406.12734, 2024 - arxiv.org
We study a closed differential form on the symmetric space of positive definite matrices,
which is defined using the Pfaffian and is $\mathsf {GL} _ {2n}(\mathbb {Z}) $ invariant up to …

On the weight zero compactly supported cohomology of

M Brandt, M Chan, S Kannan - Forum of Mathematics, Sigma, 2024 - cambridge.org
Abstract For $ g\ge 2$ and $ n\ge 0$, let $\mathcal {H} _ {g, n}\subset\mathcal {M} _ {g, n} $
denote the complex moduli stack of n-marked smooth hyperelliptic curves of genus g. A …

Discrete Morse theory for symmetric Delta-complexes

CH Yun - arXiv preprint arXiv:2209.01070, 2022 - arxiv.org
We generalize Forman's discrete Morse theory to the context of symmetric $\Delta $-
complexes. As an application, we prove that the coloop subcomplex of the link of the origin …

Connected components of strata of residueless meromorphic differentials

M Lee - Geometriae Dedicata, 2024 - Springer
Generalized strata of meromorphic differentials are loci in the usual strata of differentials,
where certain sets of residues sum up to zero. They appear naturally in the boundary of the …

The wheel classes in the locally finite homology of , canonical integrals and zeta values

F Brown, O Schnetz - arXiv preprint arXiv:2402.06757, 2024 - arxiv.org
We compute the canonical integrals associated to wheel graphs, and prove that they are
proportional to odd zeta values. From this we deduce that wheel classes define explicit non …

Hopf algebras in the cohomology of , , and

F Brown, M Chan, S Galatius, S Payne - arXiv preprint arXiv:2405.11528, 2024 - arxiv.org
We describe a bigraded cocommutative Hopf algebra structure on the weight zero compactly
supported rational cohomology of the moduli space of principally polarized abelian varieties …