1 citations · 1 across the 8 of their papers we have counts for
8 papers
A note on normal generation and the first -betti number
Sam P. Fisher, Yash Lodha
In , Osin and Thom conjectured that the first -Betti number of a torsion-free discrete group is bounded above by the normal rank of the group minus one. The conjectur…
On the top-dimensional -Betti number of residually poly- groups
Sam P. Fisher, Pablo Sánchez-Peralta
Let be a residually poly- group of finite type. We prove that admits a poly- quotient with kernel satisfying $\mathrm{cd}_{\mathbb Q}(N) < \mathbb…
Novikov cohomology, finite domination, and cohomological dimension
Sam P. Fisher
We introduce the -invariant of a group of finite type, which is defined to be the subset of non-zero characters with vanishing associated top-d…
Virtual fibring of Poincaré-duality groups
Sam P. Fisher, Giovanni Italiano, Dawid Kielak
We show that a RFRS Poincaré-duality group admits a virtual epimorphism to the integers whose kernel is itself a Poincaré-duality group over every field if and only if the $L^2…
Dimension drop in residual chains
Sam P Fisher, Kevin Klinge
We give a description of the Linnell division ring of a countable residually (poly- virtually nilpotent) (RPVN) group in terms of a generalised Novikov ring, and show th…
On the cohomological dimension of kernels of maps to
Sam P. Fisher
We prove that if is a finitely generated RFRS group of cohomological dimension , then is virtually free-by-cyclic if and only if . This answers a quest…
The Hanna Neumann Conjecture for graphs of free groups with cyclic edge groups
Sam P. Fisher, Ismael Morales
The Hanna Neumann Conjecture (HNC) for a free group predicts that for all finitely generated subgroups and , where…
Algebraic fibrings of a hyperbolic -manifold
Sam P. Fisher
We show there is a finite-volume, hyperbolic -manifold that algebraically fibres with finitely presented kernel of type . This manifold is a finite cover…