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In this paper, we introduce the notions of $\alpha$-quasicomplemented and totally $\alpha$-quasicomplemented subspaces and we established some results under these contexts. We show, for example, that if $X$ is a separable or reflexive…

Functional Analysis · Mathematics 2024-03-12 A. Barbosa , A. Raposo , G. Ribeiro

In the conformal class of the standard metric on the $3$-sphere, we prove a quantitative refinement of the Andrews-De Lellis-Topping inequality in terms of a two-term distance to the set of minimizing conformal factors. This inequality is…

Analysis of PDEs · Mathematics 2026-01-06 Tobias König , Jonas W. Peteranderl

Let $\Omega$ be a smooth, bounded domain in $\mathbb R^3$ with connected boundary. It follows from work of Escobar that the Yamabe quotient of $\Omega$ is at most the Yamabe quotient of a ball, and equality holds if and only if $\Omega$ is…

Differential Geometry · Mathematics 2025-01-22 Liam Mazurowski , Xuan Yao

We introduce several homotopy equivalence relations for proper holomorphic mappings between balls. We provide examples showing that the degree of a rational proper mapping between balls (in positive codimension) is not a homotopy invariant.…

Complex Variables · Mathematics 2015-09-30 John P. D'Angelo , Jiri Lebl

We provide examples of homogeneous spaces which are neither symmetric spaces nor real cohomology spheres, yet have the property that every invariant metric is geometrically formal. We also extend the known obstructions to geometric…

Differential Geometry · Mathematics 2011-01-12 D. Kotschick , S. Terzic

The conformal barycenter of a point cloud on the sphere at infinity of the Poincar\'e ball model of hyperbolic space is a hyperbolic analogue of the geometric median of a point cloud in Euclidean space. It was defined by Douady and Earle as…

Differential Geometry · Mathematics 2023-11-01 Jason Cantarella , Henrik Schumacher

Let X be a smooth projective Berkovich space over a complete discrete valuation field K of residue characteristic zero, endowed with an ample line bundle L. We introduce a general notion of (possibly singular) semipositive (or…

Algebraic Geometry · Mathematics 2014-01-22 S. Boucksom , C. Favre , M. Jonsson

As a follow-up to work done in [7], some new insights to the structure of the socle of a semisimple Banach algebra is obtained. In particular, it is shown that the socle is isomorphic as an algebra to the direct sum of tensor products of…

Functional Analysis · Mathematics 2018-08-21 Rudi Brits , Francois Schulz

We develop the foundations of the theory of quasi-visual approximations of bounded metric spaces. Roughly speaking, these are sequences of covers of a given space for which the diameters of the sets in the covers shrink to zero and for…

Complex Variables · Mathematics 2026-01-22 Mario Bonk , Mikhail Hlushchanka , Daniel Meyer

We introduce and study a novel uniformization metric model for the quasi-Fuchsian space QF(S) of a closed oriented surface S, defined through a class of C-valued bilinear forms on S, called Bers metrics, which coincide with hyperbolic…

Differential Geometry · Mathematics 2025-07-09 Christian El Emam

We develop a new functional-analytic technique for investigating the degree of noncompactness of an operator defined on a quasinormed space and taking values in a Marcinkiewicz space. The main result is a general principle from which it can…

Functional Analysis · Mathematics 2025-11-25 Jan Malý , Zdeněk Mihula , Vít Musil , Luboš Pick

Quasi-Boolean algebras were introduced as the generalization of Boolean algebras in the setting of quantum computation logic. In this paper, we investigate the completeness and congruences of quasi-Boolean algebras. First, we discuss the…

Logic · Mathematics 2025-10-28 Xiaohao Liu , Heyan Wang , Wenjuan Chen

We show that in complete metric spaces, $4$-hyperconvexity is equivalent to finite hyperconvexity. Moreover, every complete, almost $n$-hyperconvex metric space is $n$-hyperconvex. This generalizes among others results of Lindenstrauss and…

Metric Geometry · Mathematics 2016-10-12 Benjamin Miesch , Maël Pavón

The paper sketches a recent progress and formulates several open problems in studying equivariant quasiconformal and quasisymmetric homeomorphisms in negatively curved spaces as well as geometry and topology of noncompact geometrically…

Differential Geometry · Mathematics 2009-09-07 Boris Apanasov

With a simple generic approach, we develop a classification that encodes and measures the strength of completeness (or compactness) properties in various types of spaces and ordered structures. The approach also allows us to encode notions…

General Topology · Mathematics 2020-12-01 Hanna Ćmiel , Franz-Viktor Kuhlmann , Katarzyna Kuhlmann

In this manuscript, we claim that the newly introduced $\mathcal{F}$-metric space \cite[\, M.~Jleli and B.~Samet, On a new generalization of metric spaces, J. Fixed Point Theory Appl, 20(3) 2018]{JS1} is metrizable. Also, we deduce that the…

Functional Analysis · Mathematics 2018-08-09 Sumit Som , Ashis Bera , Lakshmi Kanta Dey

We extend Raynaud's theory of formal models from rigid-analytic spaces over a nonarchimedean field to uniform qcqs adic spaces $X$, with no finite-type assumptions, over an arbitrary Tate affinoid base $S$. The key new ingredient is the…

Algebraic Geometry · Mathematics 2025-07-16 Dimitri Dine

We give a new completion for the quasi-uniform spaces. We call the whole procedure {\it $\tau$-completion} and the new space {\it $\tau$-complement of the given}. The basic result is that every $T_{_0}$ quasi-uniform space has a…

General Topology · Mathematics 2010-08-10 Athanasios Andrikopoulos , John Stabakis

In the study of immersed surfaces of constant positive extrinsic curvature in space-forms, it is natural to substitute completeness for a weaker property, which we here call quasicompleteness. We determine the global geometry of such…

Differential Geometry · Mathematics 2024-02-28 Graham Smith

Associated to any affine space A endowed with a metric structure of arbitrary signature we consider the space of affine functionals operating on the space of quadratic functions of A. On this functional space we characterize a symmetric…

Metric Geometry · Mathematics 2023-05-04 Ana Casimiro , Cesar Rodrigo