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Let $G$ be a connected, real semisimple Lie group. Let $K<G$ be maximal compact, and let $\Gamma < G$ be discrete and such that $\Gamma \backslash G$ has finite volume. If the real rank of $G$ is $1$ and $\Gamma$ is torsion-free, then…

K-Theory and Homology · Mathematics 2025-05-06 Hao Guo , Peter Hochs , Hang Wang

In this paper we prove a tertiary index theorem which relates a spectral geometric and a homotopy theoretic invariant of an almost complex manifold with framed boundary. It is derived from the index theoretic and homotopy theoretic versions…

Algebraic Topology · Mathematics 2009-09-11 Ulrich Bunke , Niko Naumann

We study the space of pseudo-holomorphic spheres in compact symplectic manifolds with convex boundary. We show that the theory of Gromov-Witten invariants can be extended to the class of semi-positive manifolds with convex boundary. This…

Symplectic Geometry · Mathematics 2013-02-06 Sergei Lanzat

We introduce a new class of natural, explicitly defined, transversally elliptic differential operators over manifolds with compact group actions. Under certain assumptions, the symbols of these operators generate all the possible values of…

Differential Geometry · Mathematics 2021-01-28 Igor Prokhorenkov , Ken Richardson

Given a proper, cocompact action of a Lie groupoid, we define a higher index pairing between invariant elliptic differential operators and smooth groupoid cohomology classes. We prove a cohomological index formula for this pairing by…

Differential Geometry · Mathematics 2014-06-06 M. J. Pflaum , H. Posthuma , X. Tang

We consider a complete Riemannian manifold, which consists of a compact interior and one or more $\varphi$-cusps: infinitely long ends of a type that includes cylindrical ends and hyperbolic cusps. Here $\varphi$ is a function of the radial…

Differential Geometry · Mathematics 2023-04-21 Peter Hochs , Hang Wang

$\Gamma$-conformal algebra is an axiomatic description of the operator product expansion of chiral fields with simple poles at finitely many points. We classify these algebras and their representations in terms of Lie algebras and their…

q-alg · Mathematics 2009-10-30 Maria Golenishcheva-Kutuzova , Victor Kac

Given an evolution algebra associated to a connected finite graph $\Gamma$, we exhibit a free action of the group of symmetries of $\Gamma$ on the set of automorphisms of the algebra. This allows us to explicitly describe this set and we…

Rings and Algebras · Mathematics 2025-06-16 Mary Luz Rodiño Montoya , Natalia A. Viana Bedoya , Carlos Henao

Relative index theorems, which deal with what happens with the index of elliptic operators when cutting and pasting, are abundant in the literature. It is desirable to obtain similar theorems for other stable homotopy invariants, not the…

K-Theory and Homology · Mathematics 2013-07-11 V. E. Nazaikinskii

We classify subalgebras of a ring of differential operators which are big in the sense that the extension of associated graded rings is finite. We show that these subalgebras correspond, up to automorphisms, to uniformly ramified finite…

Rings and Algebras · Mathematics 2007-05-23 Friedrich Knop

We introduce the \Gamma-extension of the spectrum of the Laplacian of a Riemannian orbifold, where \Gamma is a finitely generated discrete group. This extension, called the \Gamma-spectrum, is the union of the Laplace spectra of the…

Differential Geometry · Mathematics 2014-06-27 Carla Farsi , Emily Proctor , Christopher Seaton

We revisit the construction of signature classes in C*-algebra K-theory, and develop a variation that allows us to prove equality of signature classes in some situations involving homotopy equivalences of noncompact manifolds that are only…

K-Theory and Homology · Mathematics 2018-10-03 Nigel Higson , Thomas Schick , Zhizhang Xie

We compute the $K$-theory of comparison $C^*$-algebra associated to a manifold with corners. These comparison algebras are an example of the abstract pseudodifferential algebras introduced by Connes and Moscovici \cite{M3}. Our calculation…

K-Theory and Homology · Mathematics 2010-05-12 Bertrand Monthubert , Victor Nistor

We show that, if $\Gamma$ is a point group of $\mathbb{R}^{k+1}$ of order two for some $k\geq 2$ and $\mathcal S$ is a $k$-pseudomanifold which has a free automorphism of order two, then either $\mathcal S$ has a $\Gamma$-symmetric…

Combinatorics · Mathematics 2025-01-29 James Cruickshank , Bill Jackson , Shinichi Tanigawa

We set up an algebraic framework for the study of pseudoholomorphic discs bounding nonorientable Lagrangians, as well as equivariant extensions of such structures arising from a torus action. First, we define unital cyclic twisted…

Symplectic Geometry · Mathematics 2023-03-15 Amitai Netser Zernik

We prove an equivariant implicit function theorem for variational problems that are invariant under a varying symmetry group (corresponding to a bundle of Lie groups). Motivated by applications to families of geometric variational problems…

Differential Geometry · Mathematics 2014-12-02 Renato G. Bettiol , Paolo Piccione , Gaetano Siciliano

We develop a formula for the equivariant index of a twisted Dirac operator on a compact globally hyperbolic spacetime with timelike boundary on which a group acts isometrically, subject to APS boundary conditions. The formula is the same as…

Differential Geometry · Mathematics 2026-02-19 Onirban Islam , Lennart Ronge

Let $A$ be a graded C*-algebra. We characterize Kasparov's K-theory group $\hat{K}_0(A)$ in terms of graded *-homomorphisms by proving a general converse to the functional calculus theorem for self-adjoint regular operators on graded…

Operator Algebras · Mathematics 2016-09-07 Jody Trout

We prove that, to every abstract group $G$, we can associate a sequence of graphs $\Gamma_n$ such that the automorphism group of $\Gamma_n$ is isomorphic to $G$ and the genus of $\Gamma_n$ is an unbounded function of $n$.

Group Theory · Mathematics 2025-08-29 Marco Barbieri

Let G be a connected compact Lie group acting on a manifold M and let D be a transversally elliptic operator on M. The multiplicity of the index of D is a function on the set of irreducible representations of G. Let T be a maximal torus of…

Differential Geometry · Mathematics 2016-02-10 Michèle Vergne