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For closed oriented manifolds, we establish oriented homotopy invariance of higher signatures that come from the fundamental group of a large class of orientable 3-manifolds, including the ``piecewise geometric'' ones in the sense of…

Algebraic Topology · Mathematics 2007-05-23 Michel Matthey , Hervé Oyono-Oyono , Wolfgang Pitsch

Many of the properties of sectional category, topological complexity and homotopic distance are in fact derived from a small number of basic properties, which, once established, lead to all the others without further recourse to topology.…

Algebraic Topology · Mathematics 2025-08-26 Jean-Paul Doeraene , Mohammed El Haouari

We give explicit Fredholm conditions for classes of pseudodifferential operators on suitable singular and non-compact spaces. In particular, we include a "user's guide" to Fredholm conditions on particular classes of manifolds including…

Operator Algebras · Mathematics 2017-03-24 Catarina Carvalho , Victor Nistor , Yu Qiao

We prove that every free group G with infinitely many generators admits a Hausdorff group topology T with the following property: for every T-open neighbourhood U of the identity of G, each element g in G can be represented as a product…

General Topology · Mathematics 2019-02-05 Dmitri Shakhmatov , Víctor Hugo Yañez

We study a free fermion model where two sets of non-commuting non-projective measurements stabilize area-law entanglement scaling phases of distinct topological order. We show the presence of a topological phase transition that is of a…

Quantum Physics · Physics 2023-03-15 Graham Kells , Dganit Meidan , Alessandro Romito

We introduce a non-autonomous generalization of spatial-temporal differentiations, and prove results about probabilistically and topologically generic behaviors of certain spatial-temporal differentiations generated by endomorphisms of…

Dynamical Systems · Mathematics 2022-04-25 Idris Assani , Aidan Young

The celebrated Borel--Tits theorem provides a classification of abstract isomorphisms between (simple) isotropic groups over fields, showing that such isomorphisms arise from field isomorphisms and group-scheme isomorphisms. In this work,…

Group Theory · Mathematics 2025-10-17 Pavel Gvozdevsky

We give a "limit-free formula" simplifying the computation of the topological entropy for topological automorphisms of totally disconnected locally compact groups. This result allows us to extend several basic properties of the topological…

General Topology · Mathematics 2014-01-16 Anna Giordano Bruno

Using ideas from 3-manifolds, Hatcher--Wahl defined a notion of automorphism groups of free groups with boundary. We study their Torelli subgroups, adapting ideas introduced by Putman for surface mapping class groups. Our main results show…

Geometric Topology · Mathematics 2025-03-12 Jacob Landgraf

For a given topological dynamical system $(X,T)$ over a compact set $X$ with a metric $d$, the "variational principle" states that \begin{equation*} \sup_{\mu}h_\mu(T) = h(T) = h_d(T), \end{equation*} where $h_\mu(T)$ is the…

Dynamical Systems · Mathematics 2016-04-12 André Caldas , Mauro Patrão

In order to understand the structure of the `typical' element of an automorphism group, one has to study how large the conjugacy classes of the group are. When typical is meant in the sense of Baire category, a complete description of the…

We provide groupoid models for Toeplitz and Cuntz-Krieger algebras of topological higher-rank graphs. Extending the groupoid models used in the theory of graph algebras and topological dynamical systems to our setting, we prove results on…

Operator Algebras · Mathematics 2007-05-23 Trent Yeend

Let $X$ be the Gromov-Hausdorff limit of a sequence of pointed complete K\"ahler manifolds $(M^n_i, p_i)$ satisfying $Ric(M_i)\geq -(n-1)$ and the volume is noncollapsed. We prove that, there exists a Lie group isomorphic to $\mathbb{R}$,…

Differential Geometry · Mathematics 2016-06-30 Gang Liu

The interplay between unitary dynamics and quantum measurements induces diverse phenomena in open quantum systems with no counterparts in closed quantum systems at equilibrium. Here, we generally classify Kraus operators and their effective…

Statistical Mechanics · Physics 2025-11-12 Zhenyu Xiao , Kohei Kawabata

Let $f:M\rightarrow M$ be a $C^1$ diffeomorphism with a dominated splitting on a compact Riemanian manifold $M$ without boundary. We state and prove several sufficient conditions for the topological entropy of $f$ to be positive. The…

Dynamical Systems · Mathematics 2016-06-08 Eleonora Catsigeras , Xueting Tian

In this paper, using the topology on the set of shape morphisms between arbitrary topological spaces $X$, $Y$, $Sh(X,Y)$, defined by Cuchillo-Ibanez et al. in 1999, we consider a topology on the shape homotopy groups of arbitrary…

Algebraic Topology · Mathematics 2015-11-26 Tayyebe Nasri , Fatemeh Ghanei , Behrooz Mashayekhy , Hanieh Mirebrahimi

We show that for every $N\ge 3$ the free unitary group $U^+_N$ is topologically generated by its classical counterpart $U_N$ and the lower-rank $U^+_{N-1}$. This allows for a uniform inductive proof that a number of finiteness properties,…

Quantum Algebra · Mathematics 2019-04-09 Alexandru Chirvasitu

We build on the results of [6] to show that the homology groups $\mathrm{H}_{r_1+r_2}(Y_0(\mathcal{N}_\Sigma),\mathcal{O})_{\mathfrak{m}_\Sigma}$ of arithmetic manifolds are free over certain deformation rings $R_\Sigma$, when there are…

Number Theory · Mathematics 2024-11-26 Srikanth B. Iyengar , Chandrashekhar B. Khare , Jeffrey Manning

Let $\phi$ be an automorphism of a free group $F_n$ of rank $n$, and let $M_{\phi}=F_n \rtimes_{\phi} \mathbb{Z}$ be the corresponding mapping torus of $\phi$. We study the group $Out(M_{\phi})$ under certain technical conditions on $\phi$.…

Group Theory · Mathematics 2007-05-23 O. Bogopolski , A. Martino , E. Ventura

We extend a well-studied ODE model for collective behaviour by considering anisotropic interactions among individuals. Anisotropy is modelled by limited sensorial perception of individuals, that depends on their current direction of motion.…

Classical Analysis and ODEs · Mathematics 2014-06-05 Joep H. M. Evers , Razvan C. Fetecau , Lenya Ryzhik