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pro vyhledávání: '"Bridson, Martin R"'
Autor:
Bridson, Martin R.
For every natural number $n$, there exist finitely presented groups with residual finiteness depths $\omega\cdot n$ and $\omega\cdot n + 1$. The ordinals that arise as the residual finiteness depth of a finitely generated group (equivalently, a count
Externí odkaz:
http://arxiv.org/abs/2411.07757
Autor:
Bridson, Martin R., Piwek, Paweł
A free-by-cyclic group $F_N\rtimes_\phi\mathbb{Z}$ has non-trivial centre if and only if $[\phi]$ has finite order in ${\rm{Out}}(F_N)$. We establish a profinite ridigity result for such groups: if $\Gamma_1$ is a free-by-cyclic group with non-trivia
Externí odkaz:
http://arxiv.org/abs/2409.20513
Autor:
Bridson, Martin R., Short, Hamish
Publikováno v:
Bull. Aust. Math. Soc. 110 (2024) 136-144
Every countable group $G$ can be embedded in a finitely generated group $G^*$ that is hopfian and complete, i.e. $G^*$ has trivial centre and every epimorphism $G^*\to G^*$ is an inner automorphism. Every finite subgroup of $G^*$ is conjugate to a fi
Externí odkaz:
http://arxiv.org/abs/2312.08913
Autor:
Bridson, Martin R.
Given an arbitrary, finitely presented, residually finite group $\Gamma$, one can construct a finitely generated, residually finite, free-by-free group $M_\Gamma = F_\infty\rtimes F_4$ and an embedding $M_\Gamma \hookrightarrow (F_4\ast \Gamma)\times
Externí odkaz:
http://arxiv.org/abs/2312.06539
Let $\Phi$ be a pseudo-Anosov diffeomorphism of a compact (possibly non-orientable) surface $\Sigma$ with one boundary component. We show that if $b \in \pi_1(\Sigma)$ is the boundary word, $\phi \in {\rm{Aut}}(\pi_1(\Sigma))$ is a representative of
Externí odkaz:
http://arxiv.org/abs/2312.03535
We prove that if $G$ fibres algebraically and is part of a $\mathrm{PD}^3$-pair, then $G$ is the fundamental group of a fibred compact aspherical 3-manifold. This yields a new, homological proof of a classical theorem of Stallings: if $G = \pi_1(M^3)
Externí odkaz:
http://arxiv.org/abs/2307.10725
Autor:
Bridson, Martin R., Wade, Richard D.
Publikováno v:
Geom. Funct. Anal. (2024)
For $N \geq 3$, the abstract commensurators of both ${{\rm{Aut}}}(F_N)$ and its Torelli subgroup ${{\rm{IA}}}_N$ are isomorphic to ${{\rm{Aut}}}(F_N)$ itself.
Comment: 30 pages, 5 figures. Version accepted to appear in GAFA
Comment: 30 pages, 5 figures. Version accepted to appear in GAFA
Externí odkaz:
http://arxiv.org/abs/2306.13437
Autor:
Bestvina, Mladen, Bridson, Martin R
We establish the following non-abelian analogue of the Fundamental Theorem of Projective Geometry: the natural map from ${\rm{Aut}}(F_n)$ to the automorphism group of the free-factor complex $\mathcal{AF}_n$ is an isomorphism. We also prove the corre
Externí odkaz:
http://arxiv.org/abs/2306.05941
Autor:
Bridson, Martin R.
We describe a flexible construction that produces triples of finitely generated, residually finite groups $M\hookrightarrow P \hookrightarrow \Gamma$, where the maps induce isomorphisms of profinite completions $\widehat{M}\cong\widehat{P}\cong\wideh
Externí odkaz:
http://arxiv.org/abs/2304.02357