2 citations · 4 across the 7 of their papers we have counts for
7 papers
Formulas for Hadamard coefficients in terms of Green's operators
Lennart Ronge
We describe various ways of obtaining the Hadamard coefficients associated to a normally hyperbolic operator from the corresponding Green's operators. As the Hadamard expansion on…
A Lorentzian Equivariant Index Theorem
Onirban Islam, Lennart Ronge
We develop a formula for the equivariant index of a twisted Dirac operator on a compact globally hyperbolic spacetime with timelike boundary on which a group acts isometrically, su…
Perturbations of APS Boundary Conditions for Lorentzian Dirac Operators
Lennart Ronge
We study how far APS boundary conditions for a Lorentzian Dirac operator may be perturbed without destroying Fredholmness of the Dirac operator. This is done by developing criteria…
Hadamard expansions for powers of causal Green's operators and "resolvents''
Lennart Ronge
We derive an asymptotic expansion analogous to the Hadamard expansion for powers of advanced/retarded Green's operators associated to a normally hyperbolic operator , as well as…
Extracting Hadamard Coefficients from Green's Operators
Lennart Ronge
We develop a formula for the diagonal values of the Hadamard coefficients associated to a normally hyperbolic operator on a globally hyperbolic spacetime in terms of the advanced a…
The APS-index and the spectral flow
Koen van den Dungen, Lennart Ronge
We study the Atiyah-Patodi-Singer (APS) index, and its equality to the spectral flow, in an abstract, functional analytic setting. More precisely, we consider a (suitably continuou…
Index Theory for Globally Hyperbolic Spacetimes
Lennart Ronge
An equality between the spectral flow of a family of self-adjoint Fredholm operators and the index of the associated differential operator with Atiyah-Patodi-…