Spectral invariance for certain algebras of pseudodifferential operators

Boundaries, eta invariant and the determinant bundle

Cobordism invariance shows that the index, in K-theory, of a family of pseudodifferential operators on the boundary of a fibration vanishes if the symbol family extends to be elliptic across the whole fibration. For Dirac operators with spectral boundary condition, Dai and Freed \cite{dai-freed1} gave an explicit version of this at the level of the determinant bundle. Their result, that the eta invariant of the interior family trivializes the determinant bundle of the boundary family, is extended here to the wider context of pseudodifferential families of cusp type.

C*-Algebra-valued-symbol pseudodifferential operators: abstract characterizations

Given a separable unital C*algebra $C$, let $E_n$ denote the Hilbert module equal to the completion of the Schwartz space of rapidly decreasing smooth functions from $R^n$ to $C$ equipped with the $C$-valued inner product given by integration. Let $B$ denote the space of all smooth functions with bounded derivatives from $R^n$ to $C$. For each $a$ in $B$, let $O(a)$ denote the pseudodifferential operator of symbol $a$. $O$ maps $B$ to $H$, the set of all adjointable operators on $E_n$ which have smooth orbit under the canonical action of the Heisenberg group. We construct a left inverse for $O…

A Canonical Trace Associated with Certain Spectral Triples

In the abstract pseudodifferential setup of Connes and Moscovici, we prove a general formula for the discrepancies of zeta-regularised traces associated with certain spectral triples, and we introduce a canonical trace on operators, whose order lies outside (minus) the dimension spectrum of the spectral triple.

A $C^*$-algebraic approach to the principal symbol II

We introduce an abstract theory of the principal symbol mapping for pseudodifferential operators extending the results of a preceding paper and providing a simple algebraic approach to the theory of pseudodifferential operators in settings important in noncommutative geometry. We provide a variant of Connes' trace theorem which applies to certain noncommutative settings, with a minimum of technical preliminaries. Our approach allows us to consider in a operators with non-smooth symbols, and we demonstrate the power of our approach by extending Connes' trace theorem to operators with non-smooth…

The $K$-groups and the index theory of certain comparison $C^*$-algebras

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 is obtained by showing that the comparison algebras are a homomorphic image of a groupoid $C^*$-algebra. We then prove an index theorem with values in the $K$-theory groups of the comparison algebra.

Desingularization of Lie groupoids and pseudodifferential operators on singular spaces

We introduce and study a "desingularization" of a Lie groupoid $G$ along an "$A(G)$-tame" submanifold $L$ of the space of units $M$. An $A(G)$-tame submanifold $L \subset M$ is one that has, by definition, a tubular neighborhood on which $A(G)$ becomes a thick pull-back Lie algebroid. The construction of the desingularization $[[G:L]]$ of $G$ along $L$ is based on a canonical fibered pull-back groupoid structure result for $G$ in a neighborhood of the tame $A(G)$-submanifold $L \subset M$. This local structure result is obtained by integrating a certain groupoid morphism, using results of Moer…

分次李群作用的 Shubin 演算

Shubin calculi for actions of graded Lie groups

本文用群胚方法为分次李群在分次向量空间上的作用建立渐近完备的 Shubin 型伪微分算子演算，刻画椭圆性、Rockland 条件、映射性质与谱。

Some conditions on Douglas algebras that imply the invariance of the minimal envelope map

We give several conditions on certain families of Douglas algebras that imply that the minimal envelope of the given algebra is the algebra itself. We also prove that the minimal envelope of the intersection of two Douglas algebras is the intersection of their minimal envelope.

On the Spectral Asymptotics of Operators on Manifolds with Ends

We deal with the asymptotic behaviour for $λ\to+\infty$ of the counting function $N_P(λ)$ of certain positive selfadjoint operators $P$ with double order $(m,μ)$, $m,μ>0$, $m\not=μ$, defined on a manifold with ends $M$. The structure of this class of noncompact manifolds allows to make use of calculi of pseudodifferential operators and Fourier Integral Operators associated with weighted symbols globally defined on $\mathbb{R}^n$. By means of these tools, we improve known results concerning the remainder terms of the Weyl Formulae for $N_P(λ)$ and show how their behaviour depends on the ratio $…

Nonlocal elliptic problems associated with actions of discrete groups on manifolds with boundary

Given a manifold with boundary endowed with an action of a discrete group on it, we consider the algebra of operators generated by elements in the Boutet de Monvel algebra of pseudodifferential boundary value problems and shift operators acting on functions on the manifold and its boundary. Under certain conditions on the group action, we construct a Chern character for symbols of elliptic elements in this algebra with values in a de Rham type cohomology of the fixed point manifolds and obtain an index formula in terms of this Chern character.