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We describe the Chow homology and cohomology of toric variety bundles, with no restrictions on the singularities of the fibre. We present the ordinary and equivariant homologies as modules over the cohomology of the base, identify the…

Algebraic Geometry · Mathematics 2025-12-08 Francesca Carocci , Leonid Monin , Navid Nabijou

We describe the singular cohomology ring, the K-ring of complex vector bundles, the Chow ring, and the Grothendieck ring of coherent sheaves of the total space of the fibre bundle with base space an irreducible nonsingular complete…

Algebraic Geometry · Mathematics 2007-05-23 P. Sankaran , V. Uma

We define the logarithmic tautological rings of the moduli spaces of Deligne-Mumford stable curves (together with a set of additive generators lifting the decorated strata classes of the standard tautological rings). While these algebras…

Algebraic Geometry · Mathematics 2025-05-15 Rahul Pandharipande , Dhruv Ranganathan , Johannes Schmitt , Pim Spelier

We study Givental's Lagrangian cone for the quantum orbifold cohomology of toric stack bundles and prove that the I-function gives points in the Lagrangian cone, namely we construct an explicit slice of the Lagrangian cone defined by the…

Algebraic Geometry · Mathematics 2017-02-27 Yunfeng Jiang , Hsian-Hua Tseng , Fenglong You

We show that the inertia stack of a topological stack is again a topological stack. We further observe that the inertia stack of an orbispace is again an orbispace. We show how a U(1)-banded gerbe over an orbispace gives rise to a flat line…

K-Theory and Homology · Mathematics 2018-11-28 Ulrich Bunke , Markus Spitzweck , Thomas Schick

We generalize the combinatorial description of the orbifold (Chen--Ruan) cohomology and of the Grothendieck ring of a Deligne--Mumford toric stack and its associated stacky fan in a lattice $N$ in the presence of a deformation parameter…

Algebraic Geometry · Mathematics 2017-08-23 R. Paul Horja

We establish some properties of the derived category of torus-equivariant coherent sheaves on a split toric stack bundle. Our main result is a semi-orthogonal decomposition of such a category.

Algebraic Geometry · Mathematics 2025-01-24 Qian Chao , Jiun-Cheng Chen , Hsian-Hua Tseng

We compute the stringy chow ring of a general Deligne-Mumford stack of the form [X/G] for a smooth variety X and diagonalizable group scheme G, working over a base field that is not necessarily algebraically closed. We then specialize to…

Algebraic Geometry · Mathematics 2025-02-04 Qiangru Kuang , Yeqin Liu , Rachel Webb , Weihong Xu

We provide a stacky fan description of the total space of certain split vector bundles, as well as their projectivization, over toric Deligne-Mumford stacks. We then specialize to the case of Hirzebruch orbifold $\mathcal{H}_{r}^{ab}$…

Algebraic Geometry · Mathematics 2020-04-29 Weikun Wang

For a toric Deligne-Mumford (DM) stack, we can consider a certain generalization of the Frobenius endomorphism. For such an endomorphism on a two-dimensional toric DM stack, we show that the push-forward of the structure sheaf generates the…

Algebraic Geometry · Mathematics 2013-06-18 Ryo Ohkawa , Hokuto Uehara

We develop a universal framework to study smooth higher orbifolds on the one hand and higher Deligne-Mumford stacks (as well as their derived and spectral variants) on the other, and use this framework to obtain a completely categorical…

Category Theory · Mathematics 2016-02-23 David Carchedi

Let $X$ be a torus manifold with locally standard action of a compact torus $T$ of half the dimension and orbit space a homology polytope. Smooth complete complex toric varieties and quasi-toric manifolds are examples of torus manifolds.…

K-Theory and Homology · Mathematics 2018-09-20 Jyoti Dasgupta , Bivas Khan , V. Uma

We prove a Givental-style mirror theorem for toric Deligne--Mumford stacks X. This determines the genus-zero Gromov--Witten invariants of X in terms of an explicit hypergeometric function, called the I-function, that takes values in the…

Algebraic Geometry · Mathematics 2015-10-28 Tom Coates , Alessio Corti , Hiroshi Iritani , Hsian-Hua Tseng

The double ramification (DR) cycle associated to a line bundle on a family of curves detects where the line bundle becomes fibrewise-trivial. The Hodge-DR Conjecture proposes a formula for powers of the first Chern class of a natural line…

Algebraic Geometry · Mathematics 2025-10-23 Alessandro Chiodo , David Holmes

Any toric Deligne-Mumford stack is a $\mu$-gerbe over the underlying toric orbifold for a finite abelian group $\mu$. In this paper we give a sufficient condition so that certain kinds of gerbes over a toric Deligne-Mumford stack are again…

Algebraic Geometry · Mathematics 2008-07-22 Yunfeng Jiang

We present a conjecture for the Chow ring of the universal moduli stack of bundles over hyperelliptic curves and prove it for rank and genus two. Consequently, we obtain explicit generators and relations to conclude that the Chow ring is…

Algebraic Geometry · Mathematics 2026-04-15 Shubham Saha

We define the Chow ring of the classifying space of a linear algebraic group. In all the examples where we can compute it, such as the symmetric groups and the orthogonal groups, it is isomorphic to a natural quotient of the complex…

Algebraic Geometry · Mathematics 2007-05-23 Burt Totaro

In this article we describe the equivariant and ordinary topological $K$-ring of a toric bundle with fiber a $T$-{\it cellular} toric variety. This generalizes the results in \cite{su} on $K$-theory of smooth projective toric bundles. We…

K-Theory and Homology · Mathematics 2025-02-04 V. Uma

In this work we study the additive orbifold cohomology of the moduli stack of smooth genus g curves. We show that this problem reduces to investigating the rational cohomology of moduli spaces of cyclic covers of curves where the genus of…

Algebraic Geometry · Mathematics 2013-12-20 Nicola Pagani , Orsola Tommasi

We generalize classical results about the topology of toric varieties to the case of projective Q-factorial T-varieties of complexity one using the language of divisorial fans. We describe the Hodge-Deligne polynomial in the smooth case,…

Algebraic Geometry · Mathematics 2017-12-07 Antonio Laface , Alvaro Liendo , Joaquín Moraga