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We show that any quantum family of maps from a non commutative space to a compact quantum metric space has a canonical quantum semi metric structure.

Operator Algebras · Mathematics 2019-07-31 Maysam Maysami Sadr

We introduce asymptotic-M\"obius (AM) maps, a large-scale analogue of quasi-M\"obius maps tailored to geometric group theory. AM-maps capture coarse cross-ratio behavior for configurations of points that lie far apart, providing a notion of…

Metric Geometry · Mathematics 2026-01-13 Georg Grützner

Although quantum channels underlie the dynamics of quantum states, maps which are not physical channels -- that is, not completely positive -- can often be encountered in settings such as entanglement detection, non-Markovian quantum…

Quantum Physics · Physics 2021-08-10 Bartosz Regula , Ryuji Takagi , Mile Gu

For a closed cocompact subgroup $\Gamma$ of a locally compact group $G$, given a compact abelian subgroup $K$ of $G$ and a homomorphism $\rho:\hat{K}\to G$ satisfying certain conditions, Landstad and Raeburn constructed equivariant…

Operator Algebras · Mathematics 2009-09-29 Hanfeng Li

We present a survey of the dual Gromov-Hausdorff propinquity, a noncommutative analogue of the Gromov-Hausdorff distance which we introduced to provide a framework for the study of the noncommutative metric properties of C*-algebras. We…

Operator Algebras · Mathematics 2021-10-05 Frederic Latremoliere

We establish several nonuniqueness results for the problem of finding complete conformal metrics with constant (fourth-order) $Q$-curvature on compact and noncompact manifolds of dimension $\geq5$. Infinitely many branches of metrics with…

Differential Geometry · Mathematics 2021-05-14 Renato G. Bettiol , Paolo Piccione , Yannick Sire

We develop a new kind of nonnegativity certificate for univariate polynomials on an interval. In many applications, nonnegative Bernstein coefficients are often used as a simple way of certifying polynomial nonnegativity. Our proposed…

Optimization and Control · Mathematics 2023-09-20 Mitchell Tong Harris , Pablo A. Parrilo

We present a self-contained analysis of a particular family of metrics over the set of non-negative integers. We show that these metrics, which are defined through a nested sequence of optimal transport problems, provide tight estimates for…

Optimization and Control · Mathematics 2022-04-21 Mario Bravo , Thierry Champion , Roberto Cominetti

Given a unital inductive limit of C*-algebras for which each C*-algebra of the inductive sequence comes equipped with a compact quantum metric of Rieffel, we produce sufficient conditions to build a compact quantum metric on the inductive…

Operator Algebras · Mathematics 2018-07-30 Konrad Aguilar

Calder\'on-Zygmund theory has been traditionally developed on metric measure spaces satisfying additional regularity properties. In the lack of good metrics, we introduce a new approach for general measure spaces which admit a Markov…

Functional Analysis · Mathematics 2019-07-18 Marius Junge , Tao Mei , Javier Parcet , Runlian Xia

This article is the introductory part of authors PhD thesis. The article presents a new coordinate invariant definition of quasiregular and quasiconformal mappings on Riemannian manifolds that generalizes the definition of quasiregular…

Differential Geometry · Mathematics 2014-08-12 Tony Liimatainen

We study the existence of Riemannian metrics with zero topological entropy on a closed manifold M with infinite fundamental group. We show that such a metric does not exist if there is a finite simply connected CW complex which maps to M in…

Differential Geometry · Mathematics 2007-05-23 Gabriel P. Paternain , Jimmy Petean

We initiate the study of the norm-squared of the momentum map as a rigorous tool in infinite dimensions. In particular, we calculate the Hessian at a critical point, show that it is positive semi-definite along the complexified orbit, and…

Differential Geometry · Mathematics 2024-05-24 Tobias Diez , Tudor S. Ratiu

We present a new general framework for metrization of Gromov-Hausdorff-type topologies on non-compact metric spaces. We also give easy-to-check conditions for separability and completeness and hence the measure theoretic requirements are…

Metric Geometry · Mathematics 2025-09-08 Ryoichiro Noda

We prove that all injective maps on positive complex matrices which preserve order and shrink spectrum are implemented by unitary or antiunitary conjugations. We show by counterexamples that all assumptions are indispensable. The result…

Functional Analysis · Mathematics 2022-04-26 Mateo Tomašević

We investigate conditions on a graph $C^*$-algebra for the existence of a faithful semifinite trace. Using such a trace and the natural gauge action of the circle on the graph algebra, we construct a smooth $(1,\infty)$-summable semfinite…

Functional Analysis · Mathematics 2007-05-23 David Pask , Adam Rennie

For the generic continuous map and for the generic homeomorphism of the Cantor space, we study the dynamics of the induced map on the space of probability measures, with emphasis on the notions of Li-Yorke chaos, topological entropy,…

Dynamical Systems · Mathematics 2023-05-09 Nilson C. Bernardes , Rômulo M. Vermersch

We consider the invariant measure of homogeneous random walks in the quarter-plane. In particular, we consider measures that can be expressed as a finite linear combination of geometric terms and present conditions on the structure of these…

Probability · Mathematics 2014-07-02 Yanting Chen , Richard J. Boucherie , Jasper Goseling

We study maps between positive definite or positive semidefinite cones of unital $C^*$-algebras. We describe surjective maps that preserve (1) the norm of the quotient or multiplication of elements; (2) the spectrum of the quotient or…

Operator Algebras · Mathematics 2024-03-13 Osamu Hatori , Shiho Oi

We show the equivalences of several notions of entropy, like a version of the topological entropy of the geodesic flow and the Minkowski dimension of the boundary, in metric spaces with convex geodesic bicombings satisfying a uniform…

Dynamical Systems · Mathematics 2021-05-26 Nicola Cavallucci