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Using a global version of the equivariant Chern character, we describe the complexified twisted equivariant K-theory of a space with a compact Lie group action in terms of fixed-point data. We apply this to the case of a compact Lie group…

Algebraic Topology · Mathematics 2014-02-26 Daniel S. Freed , Michael J. Hopkins , Constantin Teleman

We study a K-theoretic characteristic class of singular varieties, namely the equivariant motivic Chern class. We prove that the motivic Chern class is characterized by an axiom system inspired by that of "K-theoretic stable envelopes,"…

Algebraic Geometry · Mathematics 2020-08-19 Laszlo M. Feher , Richard Rimanyi , Andrzej Weber

We first retell in the K-theoretic context the heuristics of $S^1$-equivariant Floer theory on loop spaces which gives rise to $D_q$-module structures, and in the case of toric manifolds, vector bundles, or super-bundles to their explicit…

Algebraic Geometry · Mathematics 2015-09-15 Alexander Givental

We prove ultradifferentiable Chevelley restriction theorems for a wide range of ultradifferentiable classes. As a special case we find that isotropic functions, i.e., functions defined on the vector space of real symmetric matrices…

Classical Analysis and ODEs · Mathematics 2019-12-20 Armin Rainer

Given a finite group G, we develop a theory of G-equivariant noncommutative motives. This theory provides a well-adapted framework for the study of G-schemes, Picard groups of schemes, G-algebras, 2-cocycles, equivariant algebraic K-theory,…

Algebraic Geometry · Mathematics 2016-08-24 Goncalo Tabuada

We find lower bounds on the rank of a "real" vector bundle over an involutive space, such that "real" vector bundles of higher rank have a trivial summand and such that a stable isomorphism for such bundles implies ordinary isomorphism. We…

K-Theory and Homology · Mathematics 2025-06-25 Malkhaz Bakuradze , Ralf Meyer

Let G be a complex reductive Lie group acting on a compact K\"ahler manifold X and assume that the action of a maximal compact subgroup K of G is Hamiltonian. For each extreme point of the convex hull of the momentum map image, there is an…

Complex Variables · Mathematics 2025-05-13 Peter Heinzner , Christian Zöller

We introduce an equivariant algebraic kk-theory for G-algebras and G-graded algebras. We study some adjointness theorems related with crossed product, trivial action, induction and restriction. In particular we obtain an algebraic version…

K-Theory and Homology · Mathematics 2014-08-08 Eugenia Ellis

We prove a `Whitney' presentation, and a `Coulomb branch' presentation, for the torus equivariant quantum K theory of the Grassmann manifold $\mathrm{Gr}(k;n)$, inspired from physics, and stated in an earlier paper. The first presentation…

Algebraic Geometry · Mathematics 2025-09-05 Wei Gu , Leonardo C. Mihalcea , Eric Sharpe , Hao Zou

We find a single two-parameter skein relation on trivalent graphs, the quantum exceptional relation, that specializes to a skein relation associated to each exceptional Lie algebra (in the adjoint representation). If a slight strengthening…

Quantum Algebra · Mathematics 2025-04-09 Kim Morrison , Noah Snyder , Dylan P. Thurston

We give a conjectural formula for sheaves supported on (irreducible) conormal varieties inside the cotangent bundle of the Grassmannian, such that their equivariant $K$-class is given by the partition function of an integrable loop model,…

Algebraic Geometry · Mathematics 2016-12-15 A. Knutson , P. Zinn-Justin

Let G(d,n) denote the Grassmannian of d-planes in C^n and let T be the torus (C^*)^n/diag(C^*) which acts on G(d,n). Let x be a point of G(d,n) and let \bar{Tx} be the closure of the T-orbit through x. Then the class of the structure sheaf…

Algebraic Geometry · Mathematics 2007-05-23 David E Speyer

Let R be a Henselian discrete valuation ring with field of fractions K. If X is a smooth variety over K and G a torus over K, then we consider X-torsors under G. If XX/R is a model of X then, using a result of Brahm, we show that X-torsors…

Algebraic Geometry · Mathematics 2011-08-03 Martin Bright

In this paper, we employ the framework of localization algebras to compute the equivariant K-homology class of the Euler characteristic operator, a central object in studying equivariant index theory on manifolds. This approach provides a…

Algebraic Topology · Mathematics 2024-10-22 Hongzhi Liu , Hang Wang , Zijing Wang , Shaocong Xiang

Let $p$ be a prime number and let $X$ be a complex algebraic variety with an action of $\mathbb{Z}/p\mathbb{Z}$. We develop the theory of parity complexes in a certain $2$-periodic localization of the equivariant constructible derived…

Representation Theory · Mathematics 2021-03-11 Spencer Leslie , Gus Lonergan

We compare the K-theories of symplectic quotients with respect to a compact connected Lie group and with respect to its maximal torus, and in particular we give a method for computing the former in terms of the latter. More specifically,…

Symplectic Geometry · Mathematics 2007-05-23 Megumi Harada , Gregory D. Landweber

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

Using raising operators and geometric arguments, we establish formulas for the K-theory classes of degeneracy loci in classical types. We also find new determinantal and Pfaffian expressions for classical cases considered by Giambelli: the…

Algebraic Geometry · Mathematics 2019-06-05 David Anderson

We construct the Schubert basis of the torus-equivariant K-homology of the affine Grassmannian of a simple algebraic group G, using the K-theoretic NilHecke ring of Kostant and Kumar. This is the K-theoretic analogue of a construction of…

Combinatorics · Mathematics 2019-02-20 Thomas Lam , Anne Schilling , Mark Shimozono

By introducing a notion of smooth connection for unbounded $KK$-cycles, we show that the Kasparov product of such cycles can be defined directly, by an algebraic formula. In order to achieve this it is necessary to develop a framework of…

K-Theory and Homology · Mathematics 2014-04-18 Bram Mesland