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We construct positive-genus analogues of Welschinger's invariants for many real symplectic manifolds, including the odd-dimensional projective spaces and the renowned quintic threefold. In some cases, our invariants provide lower bounds for…

Symplectic Geometry · Mathematics 2018-02-27 Penka Georgieva , Aleksey Zinger

The progress of noncommutative geometry has been crucially influenced, from the beginning, by quantum physics: we review this development in recent years. The Standard Model, with its central role for the Dirac operator, led to several…

High Energy Physics - Theory · Physics 2007-05-23 Joseph C. Varilly

It is proved that a Stein manifold acted on by a connected compact Lie group is spherical if and only if there exists an antiholomorphic involution preserving each orbit of the action. This involution can be chosen equivariant with respect…

Complex Variables · Mathematics 2009-08-19 Dmitri Akhiezer

We explicitly construct Fredholm modules and spectral triples representing any element of $K$-homology groups of Hensel-Steinitz algebras.

Operator Algebras · Mathematics 2025-10-09 Shelley Hebert , Slawomir Klimek , Matt McBride

In this paper we present the solution to a longstanding problem of differential geometry: Lie's third theorem for Lie algebroids. We show that the integrability problem is controlled by two computable obstructions. As applications we…

Differential Geometry · Mathematics 2007-05-23 Marius Crainic , Rui L. Fernandes

We show that there is a stable homotopy theory of profinite spaces and use it for two main applications. On the one hand we construct an \'etale topological realization of the stable motivic homotopy theory of smooth schemes over a base…

Algebraic Geometry · Mathematics 2007-06-13 Gereon Quick

We define the category of manifolds with extended tangent bundles, we study their symmetries and we consider the analogue of equivariant cohomology for actions of Lie groups in this category. We show that when the action preserves the…

Differential Geometry · Mathematics 2007-09-27 Shengda Hu , Bernardo Uribe

We describe the construction of theta summable and finitely summable spectral triples associated to Mumford curves and some classes of higher dimensional buildings. The finitely summable case is constructed by considering the stabilization…

Quantum Algebra · Mathematics 2007-05-23 Gunther Cornelissen , Matilde Marcolli , Kamran Reihani , Alina Vdovina

Scheme-theoretic methods are used to classify ternary quadratic forms with values in line bundles over arbitrary schemes and to canonically determine the isomorphisms between them. The association of a quadratic bundle to its even Clifford…

Algebraic Geometry · Mathematics 2007-05-23 Venkata Balaji Thiruvalloor Eesanaipaadi

We show that the algebra A of a commutative unital spectral triple (A,H,D) satisfying several additional conditions, slightly stronger than those proposed by Connes, is the algebra of smooth functions on a compact spin manifold.

Operator Algebras · Mathematics 2008-02-04 Adam Rennie , Joseph C. Varilly

In this paper, we first discuss the topological properties of projective Stiefel manifolds, we compute their cohomology rings and classify their cohomology endomorphisms; Then by embedding the flag manifold of a classical Lie group into its…

Algebraic Topology · Mathematics 2015-12-31 Zhao Xu-an , Gao Hongzhu

It is proved that the (volume and orientation-preserving) quantum isometry group of a spectral triple obtained by deformation by some dual unitary 2-cocycle is isomorphic with a similar twist-deformation of the quantum isometry group of the…

Operator Algebras · Mathematics 2014-07-18 Debashish Goswami , Soumalya Joardar

We study the properties of tilting modules in the context of properly stratified algebras. In particular, we answer the question when the Ringel dual of a properly stratified algebra is properly stratified itself, and show that the class of…

Representation Theory · Mathematics 2010-04-02 Anders Frisk , Volodymyr Mazorchuk

In this paper, using the recently discovered notion of the $S$-spectrum, we prove the spectral theorem for a bounded or unbounded normal operator on a Clifford module (i.e., a two-sided Hilbert module over a Clifford algebra based on units…

Functional Analysis · Mathematics 2021-12-13 Fabrizio Colombo , David P. Kimsey

We generalize the notion of spectral triple with reality structure to spectral triples with multitwisted real structure, the class of which is closed under the tensor product composition. In particular, we introduce a multitwisted order one…

Quantum Algebra · Mathematics 2020-11-13 Ludwik Dabrowski , Andrzej Sitarz

We study noncommutative principal bundles (Hopf-Galois extensions) in the context of coquasitriangular Hopf algebras and their monoidal category of comodule algebras. When the total space is quasi-commutative, and thus the base space…

Quantum Algebra · Mathematics 2020-04-24 Paolo Aschieri , Giovanni Landi , Chiara Pagani

We study the isospectral deformations of the Eguchi-Hanson spaces along a torus isometric action in the noncompact noncommutative geometry. We concentrate on locality, smoothness and summability conditions of the nonunital spectral triples,…

Operator Algebras · Mathematics 2009-11-13 C. Yang

We generalise the construction of the Lie algebroid of a Lie groupoid so that it can be carried out in any tangent category. First we reconstruct the bijection between left invariant vector fields and source constant tangent vectors based…

Category Theory · Mathematics 2017-11-28 Matthew Burke

By replacing the category of smooth vector bundles over a manifold with the category of what we call smooth Euclidean fields, which is a proper enlargement of the former, and by considering smooth actions of Lie groupoids on smooth…

Representation Theory · Mathematics 2010-06-08 Giorgio Trentinaglia

We introduce a new spectral sequence for the study of $\mathcal{K}$-manifolds which arises by restricting the spectral sequence of a Riemannian foliation to forms invariant under the flows of $\{\xi_1,...,\xi_s\}$. We use this sequence to…

Differential Geometry · Mathematics 2022-07-12 Paweł Raźny