This volume contains the proceedings of the AMS Special Session on Singer-Hopf Conjecture in Geometry and Topology, held from March 18-19, 2023, at Georgia Institute of Technology, Atlanta, Georgia. It presents a multidisciplinary point of view on the Singer conjecture, the Hopf conjecture, the study on normalized Betti numbers, and several other intriguing questions on the fundamental group and cohomology of aspherical manifolds. This volume highlights many interesting research directions in the study of aspherical manifolds and covers a large collection of problems and conjectures about $L^2$-invariants of aspherical manifolds. It provides a snapshot of contemporary research in mathematics at the interface of geometry and topology, as well as algebraic geometry. The problems are presented from several distinct points of view, and the articles in this volume suggest possible generalizations and bridge a gap with closely related problems in differential geometry, complex algebraic geometry, and geometric topology. The volume can play a role in focusing the attention of the mathematical community on these fascinating problems which continue to resist the siege of geometers and topologists. It is our hope that this volume will become a valuable resource for early career mathematicians interested in these deep and important questions.
Survey and research articles
Dominik Kirstein, Christian Kremer and Wolfgang Luck, Some problems and
conjectures about $L^2$-invariants
Dessislava H. Kochloukova and Stefano Vidussi, with an appendix by Marco
Boggi, Finiteness properties of algebraic fibers of group extensions
Yongqiang Liu, $L^2$-type invariants for complex smooth quasi-projective
varieties: A survey
Research articles
Donu Arapura, Laurentiu G. Maxim and Botong Wang, Hodge-theoretic variants
of the Hopf and Singer conjectures
Alexander Dranishnikov, On Lipschitz cohomology of aspherical manifolds
Luca F. Di Cerbo and Michael Hull, Generalized graph manifolds, residual
finiteness, and the Singer conjecture
Mark Stern, $L_p$-cohomology and the geometry of $p$-harmonic forms
Luca F. Di Cerbo, University of Florida, Gainesville, FL.
Laurentiu G. Maxim, University of Wisconsin, Madison, WI.