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We study the equivariant oriented cohomology ring $h_T(G/P)$ of partial flag varieties using the moment map approach. We define the right Hecke action on this cohomology ring, and then prove that the respective Bott-Samelson classes in…

Algebraic Geometry · Mathematics 2016-08-24 Cristian Lenart , Kirill Zainoulline , Changlong Zhong

We prove a generalization of the orthogonality relations of Duflo and Moore for ergodic, trace-preserving group actions on von Neumann algebras that are integrable in a suitable sense. We also obtain convolution inequalities that generalize…

Operator Algebras · Mathematics 2026-05-28 Ulrik Enstad , Hannes Wendt

We define homology of ternary algebras satisfying axioms derived from particle scattering or, equivalently, from the third Reidemeister move. We show that ternary quasigroups satisfying these axioms appear naturally in invariants of…

Geometric Topology · Mathematics 2020-11-11 Maciej Niebrzydowski

Our goal is to find classes of convolution semigroups on Lie groups $G$ that give rise to interesting processes in symmetric spaces $G/K$. The $K$-bi-invariant convolution semigroups are a well-studied example. An appealing direction for…

Probability · Mathematics 2017-03-02 David Applebaum

Consider the algebraic dynamics on a torus T=G_m^n given by a matrix M in GL_n(Z). Assume that the characteristic polynomial of M is prime to all polynomials X^m-1. We show that any finite equivariant map from another algebraic dynamics…

Logic · Mathematics 2016-02-24 Zoé Chatzidakis , Ehud Hrushovski

The groups which can act semisymmetrically on a cubic graph of twice odd order are determined modulo a normal subgroup which acts semiregularly on the vertices of the graph.

Group Theory · Mathematics 2007-05-23 Chris Parker

We develop a theory of type semigroups for arbitrary twisted, not necessarily Hausdorff \'etale groupoids. The type semigroup is a dynamical version of the Cuntz semigroup. We relate it to traces, ideals, pure infiniteness, and stable…

Operator Algebras · Mathematics 2025-03-28 Bartosz K. Kwaśniewski , Ralf Meyer , Akshara Prasad

We prove two results on convex subsets of Euclidean spaces invariant under an orthogonal group action. First, we show that invariant spectrahedra admit an equivariant spectrahedral description, i.e., can be described by an equivariant…

Algebraic Geometry · Mathematics 2025-11-05 Renato G. Bettiol , Mario Kummer , Ricardo A. E. Mendes

Let $M$ denote a specific cubic fourfold that accommodates a group action by $\mathbb{Z}/3\mathbb{Z}$. Through utilization of derived Mckay correspondence, we present a new proof establishing the identification of the equivariant Kuznetsov…

Algebraic Geometry · Mathematics 2024-01-01 Xianyu Hu

We introduce group actions on polyfolds and polyfold bundles. We prove quotient theorems for polyfolds, when the group action has finite isotropy. We prove that the sc-Fredholm property is preserved under quotient if the base polyfold is…

Symplectic Geometry · Mathematics 2020-09-21 Zhengyi Zhou

The smooth action of a compact Lie group on a compact manifold can be resolved to an iterated space, as made explicit by Pierre Albin and the second author. On the resolution the lifted action has fixed isotropy type corresponding to the…

K-Theory and Homology · Mathematics 2021-01-05 Panagiotis Dimakis , Richard Melrose

A semiorthogonal decomposition for the bounded derived category (the category of perfect complexes in a non smooth case) of coherent sheaves on a Brauer Severi scheme is given. It relies on bounded derived categories (categories of perfect…

Algebraic Geometry · Mathematics 2007-05-23 Marcello Bernardara

This note extends some recent results on the derived category of a geometric invariant theory quotient to the setting of derived algebraic geometry. Our main result is a structure theorem for the derived category of a derived local quotient…

Algebraic Geometry · Mathematics 2015-02-11 Daniel Halpern-Leistner

A classical theorem of Scheunert on $G$-color Lie algebras, asserts in the case of finitely generated abelian groups, one can twist the algebra structure and the commutation bicharacter on $G$ by a 2-cocycle twist to a super-Lie $G$ graded,…

q-alg · Mathematics 2008-02-03 Horia C. Pop

The Linearization Theorem for proper Lie groupoids organizes and generalizes several results for classic geometries. Despite the various approaches and recent works on the subject, the problem of understanding invariant linearization…

Differential Geometry · Mathematics 2021-08-20 Matias del Hoyo , Mateus de Melo

Braverman and Gaitsgory gave necessary and sufficient conditions for a nonhomogeneous quadratic algebra to satisfy the Poincare-Birkhoff-Witt property when its homogeneous version is Koszul. We widen their viewpoint and consider a quotient…

Rings and Algebras · Mathematics 2012-09-26 Anne V. Shepler , Sarah Witherspoon

We consider finite groups acting on quantum (or skew) polynomial rings. Deformations of the semidirect product of the quantum polynomial ring with the acting group extend symplectic reflection algebras and graded Hecke algebras to the…

Rings and Algebras · Mathematics 2019-08-15 Viktor Levandovskyy , Anne V. Shepler

We explicitly show that symmetric Frobenius structures on a finite-dimensional, semi-simple algebra stand in bijection to homotopy fixed points of the trivial SO(2)-action on the bicategory of finite-dimensional, semi-simple algebras,…

Quantum Algebra · Mathematics 2017-07-26 Jan Hesse , Christoph Schweigert , Alessandro Valentino

Let $(F,J,\omega)$ be an almost K\"ahler manifold, $\alpha$ a $J$-holomorphic action of a compact Lie group $\hat K$ on $F$, and $K$ a closed normal subgroup of $\hat K$ which leaves $\omega$ invariant. We introduce gauge theoretical…

Symplectic Geometry · Mathematics 2009-11-07 Ch. Okonek , A. Teleman

We generalize several comparison results between algebraic, semi-topological and topological K-theories to the equivariant case with respect to a finite group.

K-Theory and Homology · Mathematics 2013-08-21 Jeremiah Heller , Jens Hornbostel