Functional calculus for Safarov pseudo-differential operators
Santiago Gómez Cobos, Michael Ruzhansky
TL;DR
This work develops a holomorphic functional calculus for Safarov-type global pseudo-differential operators on closed manifolds with a (not necessarily metric) connection. Using parameter-ellipticity, it constructs resolvent parametrices and proves that f(A) defined by a Dunford–Riesz integral remains within the same global symbol class, with a computable asymptotic symbol expansion. The approach yields concrete results for complex powers, exponentials, and logarithms of operators, and enables Szegö-type determinant formulas, heat-kernel trace expansions, and spectral ζ-functions, thus providing a robust toolkit for global spectral invariants. Overall, the paper extends Seeley's holomorphic calculus to Safarov's broader operator classes and establishes powerful trace and spectral tools for geometric analysis.
Abstract
Given a smooth, closed Riemannian manifold $(M,g)$ equipped with a linear connection $\nabla$ (not necessarily metric), we develop the holomorphic functional calculus for operators belonging to the global pseudo-differential classes $Ψ_{ρ, δ}^m\left(Ω^κ, \nabla, τ\right)$ introduced by Safarov. As a consequence of our main result, we establish a Szegö type-theorem, derive asymptotic expansion of the heat kernel trace, and calculate some associated spectral $ζ$-functions.
