Sami Douba

collaborators

3 papers

math.GR2021

Proper CAT(0) actions of unipotent-free linear groups

Sami Douba

Let $Γ$ be a finitely generated group of matrices over $C$ . We construct an isometric action of $Γ$ on a complete CAT(0) space $X$ such that the restriction of this action…

math.GR2021

Virtually unipotent curves in some non-NPC graph manifolds

Sami Douba

Let $M$ be a graph manifold containing a single JSJ torus $T$ and whose JSJ blocks are of the form $Σ \times S^{1}$ , where $Σ$ is a compact orientable surface with boundary. We show t…

math.GT2019

2-systems of arcs on spheres with prescribed endpoints

Sami Douba

Let $S$ be an $n$ -punctured sphere, with $n \geq 3$ . We prove that $(3 n)$ is the maximum size of a family of pairwise non-homotopic simple arcs on $S$ joining a fixed pair…