On the Laguerre calculus of left-invariant convolution (pseudo-differential) operators on the Heisenberg group
On the Laplace-Beltrami operator on the oscillator group.
On the multiplicity of eigenvalues of conformally covariant operators
Let be a compact Riemannian manifold and an elliptic, formally self-adjoint, conformally covariant operator of order acting on smooth sections of a bundle over . We prove that if has no rigid eigenspaces (see Definition 2.2), the set of functions for which has only simple non-zero eigenvalues is a residual set in . As a consequence we prove that if has no rigid eigenspaces for a dense set of metrics, then all non-zero eigenvalues are simple for a residual set of metrics in the -topology....
On the Neumann Problem for the Nonlinear Parabolic Equation of Eells-Sampson and Harmonie Mappings.
On the notion of -completeness of a stochastic flow on a manifold.
On the number of nodal solutions for a nonlinear elliptic problem on symmetric Riemannian manifolds.
On the order of natural differential operators and liftings
On the Paneitz energy on standard three sphere
We prove that the Paneitz energy on the standard three-sphere is bounded from below and extremal metrics must be conformally equivalent to the standard metric.
On the Paneitz energy on standard three sphere
We prove that the Paneitz energy on the standard three-sphere S3 is bounded from below and extremal metrics must be conformally equivalent to the standard metric.
On the projections of Laplacians under Riemannian submersions.
On the relation between elliptic and parabolic Harnack inequalities
We show that, if a certain Sobolev inequality holds, then a scale-invariant elliptic Harnack inequality suffices to imply its a priori stronger parabolic counterpart. Neither the relative Sobolev inequality nor the elliptic Harnack inequality alone suffices to imply the parabolic Harnack inequality in question; both are necessary conditions. As an application, we show the equivalence between parabolic Harnack inequality for on , (i.e., for ) and elliptic Harnack inequality for on .
On the rho invariant for manifolds with boundary.
On the Schrödinger heat kernel in horn-shaped domains
We prove pointwise lower bounds for the heat kernel of Schrödinger semigroups on Euclidean domains under Dirichlet boundary conditions. The bounds take into account non-Gaussian corrections for the kernel due to the geometry of the domain. The results are applied to prove a general lower bound for the Schrödinger heat kernel in horn-shaped domains without assuming intrinsic ultracontractivity for the free heat semigroup.
On the Sobolev constant and the -spectrum of a compact riemannian manifold
On the spectral flow and the index theorem for flat vector bundles
On the spectral theory and dynamics of asymptotically hyperbolic manifolds
We present a brief survey of the spectral theory and dynamics of infinite volume asymptotically hyperbolic manifolds. Beginning with their geometry and examples, we proceed to their spectral and scattering theories, dynamics, and the physical description of their quantum and classical mechanics. We conclude with a discussion of recent results, ideas, and conjectures.
On the spectral theory of the laplacian on noncompact hyperbolic manifolds
On the Spectrum of Non-Compact Manifolds with Finite Volume.
On the spectrum of Riemannian submersions with totally geodesic fibers
In this Note we give a rule to compute explicitely the spectrum and the eigenfunctions of the total space of a Riemannian submersion with totally geodesic fibers, in terms of the spectra and eigenfunctions of the typical fiber and any associated principal bundle.
On the theorem of Frobenius for complex vector fields