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These notes summarize the papers [, ] on the analysis of resolvent, Eisenstein series and scattering operator for geometrically finite hyperbolic quotients with rational non-maximal rank cusps. They complete somehow the talk given at the PDE seminar of Ecole Polytechnique in october 2005.

Following joint work with Dyatlov [], we describe the semi-classical measures associated with generalized plane waves for metric perturbation of ${ℝ}^d$, under the condition that the geodesic flow has trapped set $K$ of Liouville measure $0$.

Let $M^{\circ }$ be a complete noncompact manifold of dimension at least 3 and $g$ an asymptotically conic metric on $M^{\circ }$, in the sense that $M^{\circ }$ compactifies to a manifold with boundary $M$ so that $g$ becomes a scattering metric on $M$. We study the resolvent kernel ${(P+k^2)}^{-1}$ and Riesz transform $T$ of the operator $P={\Delta }_g+V$, where ${\Delta }_g$ is the positive Laplacian associated to $g$ and $V$ is a real potential function smooth on $M$ and vanishing at the boundary. In our first paper we assumed that $P$ has neither zero modes nor a zero-resonance...

On geometrically finite hyperbolic manifolds $\Gamma \setminus {ℍ}^d$, including those with non-maximal rank cusps, we give upper bounds on the number $N\left(R\right)$ of resonances of the Laplacian in disks of size $R$ as $R\to \infty$. In particular, if the parabolic subgroups of $\Gamma$ satisfy a certain Diophantine condition, the bound is $N\left(R\right)=𝒪\left(R^d{\left(\log R\right)}^{d+1}\right)$.

For odd-dimensional Poincaré–Einstein manifolds $(X^{n+1},g)$, we study the set of harmonic $k$-forms (for $k<n/2$) which are $C^m$ (with $m\in \mathbb{N}$) on the conformal compactification $\overline{X}$ of $X$. This set is infinite-dimensional for small $m$ but it becomes finite-dimensional if $m$ is large enough, and in one-to-one correspondence with the direct sum of the relative cohomology $H^k(\overline{X},\partial \overline{X})$ and the kernel of the Branson–Gover [3] differential operators $(L_k,G_k)$ on the conformal infinity $(\partial \overline{X},\left[h_0\right])$. We also relate the set of $C^{n-2k+1}\left({\Lambda }^k\left(\overline{X}\right)\right)$ forms in the kernel of $d+{\delta }_g$ to the conformal...