arXiv subjects

Sofiane Souaifi

Publications and source records attributed to Sofiane Souaifi.

3 recordsLinked to original sources

arXiv2020

The constant term of tempered functions on a real spherical space

Let $Z$ be a unimodular real spherical space. We develop a theory of constant terms for tempered functions on $Z$ which parallels the work of Harish-Chandra. The constant terms $f_I$ of an eigenfunction $f$ are parametrized by subsets $I$ of the set $S$ of spherical roots which determine the fine geometry of $Z$ at infinity. Constant terms are transitive i.e. $(f_J)_I=f_I$ for $I\subset J$, and our main result is a quantitative bound of the difference $f-f_I$, which is uniform in the parameter of the eigenfunction.

math.RT↗

arXiv2015

Geometric side of a local relative trace formula

Following a scheme suggested by B. Feigon, we investigate a local relative trace formula in the situation of a reductive $p$ -adic group $G$ relative to a symmetric subgroup $H= \underline{H}(F)$ where $\underline{H}$ is split over the local field $F$ of characteristic zero and $G = \underline{G} (F)$ is the restriction of scalars of $\underline{H} _{I E}$ relative to a quadratic unramified extension $E$ of $F$. We adapt techniques of the proof of the local trace formula by J. Arthur in order to get a geometric expansion of the integral over $H \times H$ of a truncated kernel associated to the regular representation of $G$.

math.RT↗

arXiv2004

Holomorphic L^p-type for sub-Laplacians on connected Lie groups

We study the problem of determining all connected Lie groups $G$ which have the following property (hlp): every sub-Laplacian $L$ on $G$ is of holomorphic $L^p$-type for $1\leq p<\infty, p\ne 2.$ First we show that semi-simple non-compact Lie groups with finite center have this property. We then apply an $L^p$-transference principle, essentially due to Anker, to show that every connected Lie group $G$ whose semi-simple quotient by its radical is non-compact has property (hlp). For the convenience of the reader, we give a self-contained proof of this transference principle, which generalizes the well-known Coifman-Weiss principle. One is thus reduced to studying compact extensions of solvable Lie groups. We extend previous work of Hebisch, Ludwig and Müller to compact extensions of certain classes of exponential solvable Lie groups.

math.CA↗