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Let $F_q$ be a finite field. A flag of $F_q$-linear codes $C_0\subsetneq C_1\subsetneq\dots\subsetneq C_s$ is said to satisfy the isometry-dual property if there exists a vector $x\in(F_q^*)^n$ such that $C_i=x\cdot C_{s-i}^\perp$, where…

Information Theory · Computer Science 2023-07-18 Maria Bras-Amorós , Alonso S. Castellanos , Luciane Quoos

If $\pi:(X,T)\to(Z,S)$ is a topological factor map between uniquely ergodic topological dynamical systems, then $(X,T)$ is called an isomorphic extension of $(Z,S)$ if $\pi$ is also a measure-theoretic isomorphism. We consider the case when…

Dynamical Systems · Mathematics 2015-02-26 Tomasz Downarowicz , Eli Glasner

We develop an algebraic version of Cartan method of equivalence or an analog of Tanaka prolongation for the (extrinsic) geometry of curves of flags of a vector space $W$ with respect to the action of a subgroup $G$ of the $GL(W)$. Under…

Differential Geometry · Mathematics 2011-10-04 Boris Doubrov , Igor Zelenko

We give an overview of the general framework of forms of Bak, Tits and Wall, when restricting to vector spaces over fields, and describe its relationship to the classical notions of Hermitian, alternating and quadratic forms. We then prove…

K-Theory and Homology · Mathematics 2020-09-09 David Sprehn , Nathalie Wahl

We prove measurable analogues of Whitney's classical theorems on weak isomorphisms of finite graphs. In the setting of locally finite graphings, we introduce a notion of weak isomorphism as an edge-measure-preserving Borel bijection that…

Combinatorics · Mathematics 2026-05-18 Márton Borbényi , Grigory Terlov , László Márton Tóth

In a neighborhood of isolated point of a domain of a metric space, a behavior of generalized quasiconformal mappings is studied. It is proved that, mappings mentioned above have continuous extension to the domain at some additional…

Complex Variables · Mathematics 2017-08-04 E. A. Sevost'yanov , A. A. Markysh

From the works of Rauzy and Thurston, we know how to construct (multiple) tilings of some Euclidean space using the conjugates of a Pisot unit $\beta$ and the greedy $\beta$-transformation. In this paper, we consider different…

Dynamical Systems · Mathematics 2012-02-21 Charlene Kalle , Wolfgang Steiner

We establish common fixed point theorems for two pairs of weakly compatible self-mappings using an auxiliary function of two variables. Unlike classical results, our theorems do not assume continuity of the mappings and require completeness…

Functional Analysis · Mathematics 2025-09-10 Babu G. V. R. , Alemayehu Negash , Sandhya M. L. , Meaza Bogale

We show that a totally geodesic submanifold of a symmetric space satisfying certain conditions admits an extension to a minimal submanifold of dimension one higher, and we apply this result to construct new examples of complete embedded…

Differential Geometry · Mathematics 2007-05-23 Claudio Gorodski

We prove some extension theorems involving uniformly continuous maps of the universal Urysohn space. We also prove reconstruction theorems for certain groups of autohomeomorphisms of this space and of its open subsets.

Metric Geometry · Mathematics 2012-10-23 Wieslaw Kubiś , Matatyahu Rubin

By de Vries duality, the category of compact Hausdorff spaces is dually equivalent to the category of de Vries algebras. In our recent article, we have extended de Vries duality to completely regular spaces by generalizing de Vries algebras…

General Topology · Mathematics 2018-04-13 Guram Bezhanishvili , Patrick J. Morandi , Bruce Olberding

We address the question of when a covering of the boundary of a surface can be extended to a covering of the surface (equivalently: when is there a branched cover with a prescribed monodromy). If such an extension is possible, when can the…

Geometric Topology · Mathematics 2014-02-26 Manfred Droste , Igor Rivin

In this paper we study a sufficient conditions for continuous and almost continuous extensions of f to space X for an image space Y with different separation axioms.

General Topology · Mathematics 2016-04-20 Alexander V. Osipov

The purpose of this paper is to address a manifold-based version of Whitney's extension problem: Given a compact set $E\subset\mathbb{R}^n$, how can we tell if there exists a $d$-dimensional, $C^m$-smooth manifold $\mathcal{M}\supset E$? We…

Functional Analysis · Mathematics 2024-01-09 Kevin O'Neill

We study the space of Riemannian metrics over a compact manifold equipped with the Ebin metric. We characterize its self-isometries and prove that two such spaces are isometric if and only if their underlying manifolds are diffeomorphic.

Metric Geometry · Mathematics 2025-12-09 David Lenze

We establish extension theorems for separately holomorphic mappings defined on sets of the form W\setminus M with values in a complex analytic space which possesses the Hartogs extension property. Here W is a 2-fold cross of arbitrary…

Complex Variables · Mathematics 2009-01-21 Viet-Anh Nguyen , Peter Pflug

We provide a sufficient condition for the continuous extension of isometries for the Kobayashi distance between bounded convex domains in complex Euclidean spaces having boundaries that are only slightly more regular than $\mathcal{C}^1$.…

Complex Variables · Mathematics 2021-12-28 Anwoy Maitra

In this thesis, we study extensions of the theory of Riemannian submanifolds in two directions. First, we will show how Riemannian geometry and submanifold theory in particular, can be generalized using the notion of 'Rinehart spaces', and…

Differential Geometry · Mathematics 2018-01-03 Victor Pessers

We show that if a graph $G$ admits a quasi-isometry $\phi$ to a graph $H$ of bounded path-width, then we can assign a non-negative integer length to each edge of $H$, such that the same function $\phi$ is a quasi-isometry to this weighted…

Combinatorics · Mathematics 2025-10-03 Tung Nguyen , Alex Scott , Paul Seymour

For a representation of a connected compact Lie group G in a finite dimensional real vector space U and a subspace V of U, invariant under a maximal torus of G, we obtain a sufficient condition for V to meet all G-orbits in U, which is also…

Representation Theory · Mathematics 2010-12-24 Jinpeng An , Dragomir Z. Djokovic