description: Generalizing the Bieri-Neumann-Strebel-Renz Invariants, this memoir presents the foundations of a theory of (not necessarily discrete) actions $ ho$ of a (suitable) group $G$ by isometries on a proper CAT(0) space $M$. It introduces the passage from groups $G$ to group actions $ ho$ that implies the introduction of 'Sigma invariants'.
language: English
title: Connectivity Properties of Group Actions on Non-Positively Curved Spaces
titlecomplete: Connectivity Properties of Group Actions on Non-Positively Curved Spaces (Memoirs of the American Mathematical Society)
publisher: Amer Mathematical Society