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We study primary and secondary invariants of leafwise Dirac operators on foliated bundles. Given such an operator, we begin by considering the associated regular self-adjoint operator $D_m$ on the maximal Connes-Skandalis Hilbert module and…

Differential Geometry · Mathematics 2008-09-15 Moulay-Tahar Benameur , Paolo Piazza

In this paper, we give a definition of the relative equivariant coarse index for proper actions and derive a relative equivariant coarse index theorem connecting this index with the localized equivariant coarse indices. This is an…

Operator Algebras · Mathematics 2020-12-17 Xiaoman Chen , Yanlin Liu , Dapeng Zhou

We consider inference of the parameters of the diffusion term for Cox-Ingersoll-Ross and similar processes with a power type dependence of the diffusion coefficient from the underlying process. We suggest some original pathwise estimates…

Probability · Mathematics 2017-04-12 Nikolai Dokuchaev

In this paper we study the Lorenz equations using the perspective of the Conley index theory. More specifically, we examine the evolution of the strange set that these equations posses throughout the different values of the parameter. We…

Dynamical Systems · Mathematics 2024-01-18 Héctor Barge , J. M. R. Sanjurjo

It is shown that if a $C^2$ surface $M\subset\mathbb R^3$ has negative curvature on the complement of a point $q\in M$, then the $\mathbb Z/2$-valued Poincar\'e-Hopf index at $q$ of either distribution of principal directions on $M-\{q\}$…

Differential Geometry · Mathematics 2014-04-10 F. Fontenele , F. Xavier

We define the "localized index" of longitudinal elliptic operators on Lie groupoids associated to Lie algebroid cohomology classes. We derive a topological expression for these numbers using the algebraic index theorem for Poisson manifolds…

K-Theory and Homology · Mathematics 2011-12-22 M. J. Pflaum , H. Posthuma , X. Tang

Cyclic cohomology has been recently adapted to the treatment of Hopf symmetry in noncommutative geometry. The resulting theory of characteristic classes for Hopf algebras and their actions on algebras allows to expand the range of…

Operator Algebras · Mathematics 2007-05-23 Alain Connes , Henri Moscovici

For a compact complex manifold, we introduce holomorphic foliations associated with certain abelian subgroups of the automorphism group. Such foliations are generalizations of holomorphic principal torus bundles. If there exists a…

Complex Variables · Mathematics 2018-01-22 Hiroaki Ishida , Hisashi Kasuya

We express the beta invariant of a loopless matroid as tropical self-intersection number of the diagonal of its matroid fan (a "local" Poincar\'e-Hopf theorem). This provides another example of uncovering the "geometry" of matroids by…

Algebraic Geometry · Mathematics 2023-02-22 Johannes Rau

This is primarily a survey of the way in which Hopf cyclic cohomology has emerged and evolved, in close relationship with the application of the noncommutative local index formula to transverse index theory on foliations. Being…

Quantum Algebra · Mathematics 2007-05-23 Alain Connes , Henri Moscovici

The Conley index for flows is a topological invariant describing the behavior around an isolated invariant set $S$. It is defined as the homotopy type of a quotient space $N/L$, where $(N,L)$ is an index pair for $S$. In the case of a…

Dynamical Systems · Mathematics 2018-01-30 Frank Weilandt

We study the dynamics of surface homeomorphisms around isolated fixed points whose Poincar\'{e}-Lefschetz index is not equal to 1. We construct a new conjugacy invariant, which is a cyclic word on the alphabet $\{\ua, \ra, \da, \la\}$. This…

Dynamical Systems · Mathematics 2016-08-16 Frédéric Le Roux

The aim of this note is threefold. The first is to obtain a simple characterization of relative constructible sheaves when the parameter space is projective. The second is to study the relative Fourier-Mukai for relative constructible…

Algebraic Geometry · Mathematics 2025-08-19 Luisa Fiorot , Teresa Monteiro Fernandes

Using recently introduced Debord-Skandalis Blup's groupoids we study index theory for a compact foliated manifold with boundary inducing a foliation in its boundary. For this we consider first a blup groupoid whose Lie algebroid has…

K-Theory and Homology · Mathematics 2021-04-15 Ibrahim Akrour , Paulo Carrillo Rouse

Many important index transforms can be constructed via the spectral theory of Sturm-Liouville differential operators. Using the spectral expansion method, we investigate the general connection between the index transforms and the associated…

Classical Analysis and ODEs · Mathematics 2018-06-18 Rúben Sousa , Semyon Yakubovich

Let $X$ be a projective algebraic $d$-variety endowed with isolated determinantal singularities, and let $\omega$ be a $1$-form on $X$ exhibiting a finite number of singularities (in the stratified sense). Under some technical conditions,…

Geometric Topology · Mathematics 2026-05-08 N. G. Grulha , M. S. Pereira , H. Santana

We develop the diffeomorphism invariant Colombeau-type algebra of nonlinear generalized functions in a modern and compact way. Using a unifying formalism for the local setting and on manifolds, the construction becomes simpler and more…

Functional Analysis · Mathematics 2013-03-14 Eduard Nigsch

We define the Chern character of the index class of a $G$-invariant family of $G$-transversally elliptic operators, see [6]. Next we study the Berline-Vergne formula for families in the elliptic and transversally elliptic case.

K-Theory and Homology · Mathematics 2019-04-24 Alexandre Baldare

We consider Reeb flows on the tight $3$-sphere admitting a pair of closed orbits forming a Hopf link. If the rotation numbers associated to the transverse linearized dynamics at these orbits fail to satisfy a certain resonance condition…

Dynamical Systems · Mathematics 2014-04-03 Umberto Hryniewicz , Al Momin , Pedro A. S. Salomão

The Poincar\'e-Hopf Theorem is a conservation law for real-analytic vector fields, which are tangential to a closed surface (such as a torus or a sphere). The theorem also governs real-analytic vector fields, which are tangential to…

Analysis of PDEs · Mathematics 2022-10-04 Aaron Pim