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We study the structure of the fibre operators corresponding to periodic magnetic pseudo-differential operators having periodic magnetic potentials. We obtain explicit formulas for their distribution kernel, both when these fibres are seen…

Analysis of PDEs · Mathematics 2026-05-19 Horia D. Cornean , Bernard Helffer , Radu Purice

Let $\Omega \subset {\bf R}^d$ be open. We investigate conditions under which an operator $T$ on $L_2(\Omega)$ has a continuous kernel $K \in C(\overline \Omega \times \overline \Omega)$. In the centre of our interest is the condition $T…

Analysis of PDEs · Mathematics 2019-03-18 W. Arendt , A. F. M. ter Elst

This article is about erroneous attempts to weaken the standard definition of unbounded Kasparov module (or spectral triple). We present counterexamples to claims in the literature that Fredholm modules can be obtained from these weaker…

K-Theory and Homology · Mathematics 2019-11-28 I. Forsyth , B. Mesland , A. Rennie

We develop two connections between the quantitative framework of operator $K$-theory for geometric $C^*$-algebras and the problem of positive scalar curvature. First, we introduce a quantitative notion of higher index and use it to give a…

K-Theory and Homology · Mathematics 2024-09-02 Hao Guo , Zhizhang Xie , Guoliang Yu

We provide a complete set of supersymmetric constraints for the anomalous dimensions of the conformal twist-two operators to all orders of perturbation theory. Employing them we derive new relations between the exclusive evolution kernels…

High Energy Physics - Phenomenology · Physics 2009-10-31 A. V. Belitsky , D. Müller

We consider a semi-classical Dirac operator in arbitrary spatial dimensions with a smooth potential whose partial derivatives of any order are bounded by suitable constants. We prove that the distribution kernel of the inverse operator…

Mathematical Physics · Physics 2011-10-18 Oliver Matte , Claudia Warmt

Dirac operators on curved space-times are introduced with the help of a new point-view that observers have to be included in the formulation of natural laws. The class of Dirac operators are Lorentz invariant in the sense that the…

General Relativity and Quantum Cosmology · Physics 2024-02-06 Zhongmin Qian

We discuss the notion of basic cohomology for Dirac structures and, more generally, Lie algebroids. We then use this notion to characterize the obstruction to a variational formulation of Dirac dynamics.

Differential Geometry · Mathematics 2023-10-25 Oscar Cosserat , Camille Laurent-Gengoux , Alexei Kotov , Leonid Ryvkin , Vladimir Salnikov

The topological non-triviality of insulating phases of matter is by now well understood through topological K-theory where the indices of the Dirac operators are assembled into topological classes. We consider in the context of the Kitaev…

Strongly Correlated Electrons · Physics 2022-09-13 Bora Basa , Gabriele La Nave , Philip W. Phillips

Using Quillen-Lurie deformation theory formalism we develop an obstruction theory for studying the stable $\infty$-category of modules over a given geometric $\infty$-stack. The obstruction theory studies the problem of lifting compact…

Algebraic Geometry · Mathematics 2012-12-11 Romie Banerjee

We develop elliptic regularity theory for Dirac operators in a very general framework: we consider Dirac operators linear over $C^*$-algebras, on noncompact manifolds, and in families which are not necessarily locally trivial fibre bundles.

Operator Algebras · Mathematics 2018-01-22 Johannes Ebert

This paper investigates the composition of Bernstein--Durrmeyer operators and Sz\'asz--Mirakjan--Durrmeyer operators, focusing on the structure and properties of the associated kernel functions. In the case of the Bernstein--Durrmeyer…

Classical Analysis and ODEs · Mathematics 2025-07-01 Ulrich Abel , Ana Maria Acu , Margareta Heilmann , Ioan Raşa

We consider a spectral problem over $\mathbb{R}^n$ for a Douglis-Nirenberg system of differential operators under limited smoothness assumptions and under the assumption of parameter-ellipticity in a closed sector $\mathcal{L}$ in the…

Analysis of PDEs · Mathematics 2016-12-28 M. Faierman

Let G be a compact connected semisimple Lie group and let H\subset G be a closed connected subgroup such that rank(G)=rank(H) and G/H is a symmetric space. Given an irreducible representation of H, we define a Dirac operator D and determine…

Representation Theory · Mathematics 2010-08-27 Emiko Dupont

Equivariant twisted K theory classes on compact Lie groups $G$ can be realized as families of Fredholm operators acting in a tensor product of a fermionic Fock space and a representation space of a central extension of the loop algebra $LG$…

Mathematical Physics · Physics 2018-08-15 Jouko Mickelsson

In this paper, we establish an integral expression for the Dunkl kernel in the context of Dihedral group of an arbitrary order by using the results in \cite{M-Y-Vk} where a construction of the Dunkl intertwining operator for a large set of…

Classical Analysis and ODEs · Mathematics 2015-09-08 M. Maslouhi

We introduce the concept of chiral geometric operators and use Gilkey's invariance theory to prove the local index theorem for these operators. In other words, we demonstrate that the supertrace of the heat kernel of a given geometric…

Differential Geometry · Mathematics 2026-05-27 Alberto Richtsfeld

Graphene is famous for being a host of 2D Dirac fermions. However, spin-orbit coupling introduces a small gap, so that graphene is formally a quantum spin hall insulator. Here we present symmetry-protected 2D Dirac semimetals, which feature…

Materials Science · Physics 2015-09-23 Steve M. Young , Charles L. Kane

We introduce a Banach Lie group $G$ of unitary operators subject to a natural trace condition. We compute the homotopy groups of $G$, describe its cohomology and construct an $S^1$-central extension. We show that the central extension…

K-Theory and Homology · Mathematics 2016-08-29 Pedram Hekmati , Jouko Mickelsson

Let $\Y$ be a smooth connected manifold, $\Sigma\subset\C$ an open set and $(\sigma,y)\to\scrP_y(\sigma)$ a family of unbounded Fredholm operators $D\subset H_1\to H_2$ of index 0 depending smoothly on $(y,\sigma)\in \Y\times \Sigma$ and…

Analysis of PDEs · Mathematics 2013-01-25 Thomas Krainer , Gerardo A. Mendoza