A. Zeghib

activity

20242026

collaborators

17 papers

math.DG2026

A local Lorentzian Ferrand-Obata theorem for conformal vector fields

Sorin Dumitrescu, Charles Frances, Karin Melnick +2

For a conformal vector field on a closed, real-analytic, Lorentzian manifold we prove that the flow is locally isometric -- that it preserves a metric in the conformal class on a n…

math.DG2026

Arithmetic structure of generalized Inoue--Bombieri manifolds

Brice Flamencourt, Abdelghani Zeghib

A Generalized Inoue--Bombieri (GIB) manifold $M$ is a compact quotient of a connected Riemannian product $R^{q} \times (N, g_{N})$ by a discrete subgroup of $\mathrm{Sim}(\mat…

math.DG2026

Locally conformally homogeneous Lorentzian spaces

Thomas Leistner, Lilia Mehidi, Abdelghani Zeghib

We study locally conformally homogeneous Lorentzian manifolds of dimension at least $3$ , admitting an essential pseudo-group of local conformal transformations. Generalizing a rece…

math.DG2026

Isometries of spacetimes without observer horizons

Leonardo GarcÃa-Heveling, Abdelghani Zeghib

We study the isometry groups of (non-compact) Lorentzian manifolds with well-behaved causal structure, aka causal spacetimes satisfying the ``no observer horizons'' condition. Our…

math.DG2025

On the Inoue-Bombieri construction

Brice Flamencourt, Abdelghani Zeghib

We study compact quotients of a Riemannian product $R^{q} \times (N, g_{N})$ , where $(N, g_{N})$ is a complete Riemannian manifold, by discrete subgroups $I^$ of $\mathrm{Sim}(\…

math.DG2025

Pseudo-Conformal actions of semisimple Lie groups

Mehdi Belraouti, Mohamed Deffaf, Abdelghani Zeghib

We consider the pseudo-Riemannian Lichnerowicz conjecture in the homogeneous setting. In particular, we show that any compact connected pseudo-Riemannian manifold $M$ on which a se…