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Aarhus Universitets segl

A Taylor-like Expansion of a Commutator with a Function of Self-adjoint, Pairwise Commuting Operators

by Morten Grud Rasmussen
Preprints Number 1 (March 2010)

Let A be a ν-vector of self-adjoint, pairwise commuting operators and B a bounded operator of class Cn0(A). We prove a Taylor-like expansion of the commutator [B,f(A)] for a large class of functions f:RνR, generalising the one-dimensional result where A is just a self-adjoint operator. This is done using almost analytic extensions and the higher-dimensional Helffer-Sjöstrand formula.

Keywords: Commutator expansions, functional calculus, almost analytic extensions, Helffer-Sjöstrand formula.

Mathematical Subject Classification (2010): 47B47

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