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Совместный модуль вариации функций и условно регулярный принцип выбора
С. 399-402.
С.А.Чистякова, В.В.Чистяков
Given a closed interval $I=[a,b]$ and a metric space $(M,d)$, we introduce a
nondecreasing sequence $\{\nu_n\}$ of pseudometrics on $M^I$ (the set of all
functions from $I$ into $M$), called the {\it joint modulus of variation}. We show that
if two sequences of functions $\{f_j\}$ and $\{g_j\}$ from $M^I$ are such that
$\{f_j\}$ is pointwise relatively compact on $I$, $\{g_j\}$ is pointwise convergent on $I$,
and $\limsup_{j\to\infty}\nu_n(f_j,g_j)=o(n)$ as $n\to\infty$, then $\{f_j\}$ admits
a pointwise convergent subsequence whose limit on $I$ is a conditionally regulated function.
In book
Т. 54: Теория функций, ее приложения и смежные вопросы. , Каз. : Издательство Казанского математического общества и Академии наук РТ, 2017
Vyacheslav V. Chistyakov, Svetlana A. Chistyakova, Studia Mathematica 2017 Vol. 238 No. 1 P. 37-57
Given a subset $T$ of the reals $R$ and a metric space $M$, we introduce a nondecreasing sequence $\{\nu_n\}$ of pseudometrics on $M^T$ (the set of all functions from $T$ into $M$), called the joint modulus of variation. We prove that if two sequences $\{f_j\}$ and $\{g_j\}$ of functions from $M^T$ are such that $\{f_j\}$ ...
Added: May 11, 2017
Vyacheslav V. Chistyakov, Svetlana A. Chistyakova, / Cornell University. Series math "arxiv.org". 2016. No. 1601.07298.
Given a subset T of real numbers and a metric space M, we introduce a nondecreasing sequence {v_n} of pseudometrics on the set M^T of all functions from T into M, called the joint modulus of variation. We prove that if two sequences of functions {f_j} and {g_j} from M^T are such that {f_j} is ...
Added: February 12, 2016
Vyacheslav V. Chistyakov, / Cornell University Library, NY, USA. Series arXiv [math.FA] "Functional Analysis". 2019. No. arXiv: 1910.08490.
Let $T\subset\mathbb{R}$, $M$ be a metric space with metric $d$, and $M^T$ be the set of all functions mapping $T$ into $M$. Given $f\in M^T$, we study the properties of the approximate variation $\{V_\varepsilon(f)\}_{\varepsilon>0}$, where $V_\varepsilon(f)$ is the greatest lower bound of Jordan variations $V(g)$ of functions $g\in M^T$ such that $d(f(t),g(t))\le\varepsilon$ for all $t\in T$. The notion of $\varepsilon$-variation ...
Added: October 21, 2019
Vyacheslav V. Chistyakov, Svetlana A. Chistyakova, / Cornell University, NY, USA. Series arXiv [math.FA] "Functional Analysis". 2020. No. 2010.11410.
Let $T\subset\mathbb{R}$ and $(X,\mathcal{U})$ be a uniform space with an at most countable gage of pseudometrics $\{d_p:p\in\mathcal{P}\}$ of the uniformity $\mathcal{U}$. Given $f\in X^T$ (=\,the family of all functions from $T$ into $X$), the {\em approximate variation\/} of $f$ is the two-parameter family $\{V_{\varepsilon,p}(f):\varepsilon>0,p\in\mathcal{P}\}$, where $V_{\varepsilon,p}(f)$ is the greatest lower bound of Jordan's variations $V_p(g)$ ...
Added: October 23, 2020
V. V. Chistyakov, S. A. Chistyakova, Lobachevskii Journal of Mathematics 2022 Vol. 43 No. 3 P. 550-563
Given a Hausdorff uniform space X with the countable gage of pseudometrics of the
uniformity of X, we introduce a concept of the approximate variation of a function f mapping a
subset T of the reals intoX: this is the infimum of the family of Jordan-type variations of all functions
g : T → X which differ from ...
Added: April 30, 2022
Vyacheslav V. Chistyakov, Svetlana A. Chistyakova, Journal of Mathematical Analysis and Applications 2017 Vol. 452 No. 2 P. 970-989
We introduce a pseudometric TV on the set M^X of all functions mapping a rectangle X on the plane R^2 into a metric space M, called the total joint variation. We prove that if two sequences {fj} and {gj} of functions from M^X are such that {fj} is pointwise precompact on X, {gj} is pointwise ...
Added: April 13, 2017
Tretyachenko Y., Russian Mathematics 2010 Vol. 54 No. 5 P. 35-46
In this paper we consider sequences of functions that are defined on a subset of the real line and take on values in a uniform Hausdorff space. For such sequences we obtain a sufficient condition for the existence of pointwise convergent subsequences. We prove that this generalization of the Helly theorem includes many results of ...
Added: November 14, 2012
Vyacheslav V. Chistyakov, Tretyachenko Y. V., Journal of Mathematical Analysis and Applications 2013 Vol. 402 No. 2 P. 648-659
Given a rectangle in the real Euclidean n-dimensional space and two maps f and g defined on it and taking values in a metric semigroup, we introduce the notion of the total joint variation TV(f , g) of these maps. This extends similar notions considered by Hildebrandt (1963) [17], Leonov (1998) [18], Chistyakov (2003, 2005) ...
Added: August 29, 2013
Vyacheslav V. Chistyakov, Springer, 2021
This book addresses the minimization of special lower semicontinuous functionals
over (closed) balls in metric spaces, called the approximate variation. The new
notion of approximate variation contains more information about the bounded
variation functional and has the following features: the infimum in the definition
of approximate variation is not attained in general and the total Jordan variation
of a function ...
Added: October 29, 2021
Tretyachenko Y., Известия высших учебных заведений. Математика 2010 № 5 С. 41-54
In this paper we consider sequences of functions that are defined on a subset of the real line with values in a uniform Hausdorff space. For such sequences we obtain a sufficient condition for the existence of pointwise convergent subsequences. We prove that this generalization of the Helly theorem includes many results of the recent ...
Added: September 28, 2012
Chistyakov V., Tretyachenko Y., Journal of Mathematical Analysis and Applications 2010 Vol. 370 No. 2 P. 672-686
Given two points a=(a1,…,an) and b=(b1,…,bn) from Rn with a<b componentwise and a map f from the rectangle <img src="http://ars.els-cdn.com/content/image/1-s2.0-S0022247X10003574-si5.gif" /> into a metric semigroup M=(M,d,+), we study properties of the total variation<img src="http://ars.els-cdn.com/content/image/1-s2.0-S0022247X10003574-si7.gif" /> of f on <img src="http://ars.els-cdn.com/content/image/1-s2.0-S0022247X10003574-si8.gif" /> introduced by the first author in [V.V. Chistyakov, A selection principle for mappings of ...
Added: November 22, 2012
Chistyakov V., Tretyachenko Y., Journal of Mathematical Analysis and Applications 2010 Vol. 369 No. 1 P. 82-93
Given a=(a1,…,an), b=(b1,…,bn)∈Rn with ab componentwise and a map f from the rectangle Iab=[a1,b1]×⋯×[an,bn] into a metric semigroup M=(M,d,+), denote by TV(f,Iab) the Hildebrandt–Leonov total variation of f on Iab, which has been recently studied in [V.V. Chistyakov, Yu.V. Tretyachenko, Maps of several variables of finite total variation. I, J. Math. Anal. Appl. (2010), submitted ...
Added: January 9, 2013
Vyacheslav V. Chistyakov, Switzerland : Springer, 2015
Aimed toward researchers and graduate students familiar with elements of functional analysis, linear algebra, and general topology; this book contains a general study of modulars, modular spaces, and metric modular spaces. Modulars may be thought of as generalized velocity fields and serve two important purposes: generate metric spaces in a unified manner and provide a ...
Added: December 31, 2015
Bufetov A., Klimenko A. V., Series C., Commentarii Mathematici Helvetici 2023 Vol. 98 No. 1 P. 41-134
We prove pointwise convergence of spherical averages for a measure-preserving action of a Fuchsian group. The proof is based on a new variant of the Bowen–Series symbolic coding for Fuchsian groups that, developing a method introduced by Wroten, simultaneously encodes all possible shortest paths representing a given group element. The resulting coding is self-inverse, giving ...
Added: February 29, 2024
Klimenko A. V., Bufetov A., Series C., / Cornell University. Series math "arxiv.org". 2018. No. 1805.11743.
Pointwise convergence of spherical averages is proved for a measure-preserving action of a Fuchsian group. The proof is based on a new variant of the Bowen-Series symbolic coding for Fuchsian groups that, developing a method introduced by Wroten, simultaneously encodes all possible shortest paths representing a given group element. The resulting coding is self-inverse, giving ...
Added: September 18, 2018
Vyacheslav V. Chistyakov, / Cornell University, NY, USA. Series arXiv [math.FA] "Functional Analysis". 2019. No. 1901.09722.
Under certain initial conditions, we prove the existence of set-valued selectors of univariate compact-valued multifunctions of bounded (Jordan) variation when the notion of variation is defined taking into account only the Pompeiu asymmetric excess between compact sets from the target metric space. For this, we study subtle properties of the directional variations. We show by examples that all assumptions ...
Added: January 29, 2019
Delon J., Salomon J., Sobolevski A., Journal of Mathematical Sciences 2012 Vol. 181 No. 6 P. 782-791
We consider a minimum-weight perfect matching problem on the line and establish a "bottom-up" recursion relation for partial minimum-weight matchings. ...
Added: May 11, 2012
Chistyakov V., Nonlinear Analysis 2010 Vol. 72 No. 1 P. 1-14
The notion of a modular is introduced as follows. A (metric) modular on a set X is a function w:(0,∞)×X×X→[0,∞] satisfying, for all x,y,z∈X, the following three properties: x=y if and only if w(λ,x,y)=0 for all λ>0; w(λ,x,y)=w(λ,y,x) for all λ>0; w(λ+μ,x,y)≤w(λ,x,z)+w(μ,y,z) for all λ,μ>0. We show that, given x0∈X, the set Xw={x∈X:limλ→∞w(λ,x,x0)=0} is a ...
Added: September 26, 2012
Ponomarenko A., Avrelin N., Naidan B. et al., , in : DATA ANALYTICS 2014, The Third International Conference on Data Analytics. : [б.и.], 2014. P. 125-130.
Similarity searching has a vast range of applications in various fields of computer science. Many methods have been proposed for exact search, but they all suffer from the curse of dimensionality and are, thus, not applicable to high dimensional spaces. Approximate search methods are considerably more efficient in high dimensional spaces. Unfortunately, there are few ...
Added: October 15, 2014
Ponomarenko A., Avrelin N., Найдан Б. С. et al., Алгоритмы, методы и системы обработки данных 2015 Т. 4 № 33 С. 91-106
Поиск по похожести широко применяется в различных областях компьютерных наук. Множество методов было предложено для решения задачи в точной постановке, однако все они подвержены "проклятью" размерности и не эффективны для данных высокой размерности. Приближенные алгоритмы отчасти позволяют справиться с "проклятьем". Однако из-за сложной стохастической природы, теоретические оценки для большинства приближенных алгоритмов отсутствуют. Более того, на ...
Added: September 27, 2016
Chistyakov V., Nonlinear Analysis 2010 Vol. 72 No. 1 P. 15-30
The notion of a modular is introduced as follows. A (metric) modular on a set X is a function w:(0,∞)×X×X→[0,∞] satisfying, for all x,y,z∈X, the following three properties: x=y if and only if w(λ,x,y)=0 for all λ>0; w(λ,x,y)=w(λ,y,x) for all λ>0; w(λ+μ,x,y)≤w(λ,x,z)+w(μ,y,z) for all λ,μ>0. We show that, given x0∈X, the set Xw={x∈X:limλ→∞w(λ,x,x0)=0} is a ...
Added: January 25, 2013
Beaudou L., Bondy A., Chen X. et al., Combinatorica 2013 Vol. 33 No. 6 P. 633-654
One of the De Bruijn-Erdős theorems deals with finite hypergraphs where every two vertices belong to precisely one hyperedge. It asserts that, except in the perverse case where a single hyperedge equals the whole vertex set, the number of hyperedges is at least the number of vertices and the two numbers are equal if and ...
Added: April 11, 2019
Yury M., Ponomarenko A., Vladimir K. et al., Lecture Notes in Computer Science 2012 No. 7404 P. 132-147
We propose a novel approach for solving the approximate nearest neighbor search problem in arbitrary metric spaces. The distinctive feature of our approach is that we can incrementally build a non-hierarchical distributed structure for given metric space data with a logarithmic complexity scaling on the size of the structure and adjustable accuracy probabilistic nearest neighbor ...
Added: October 1, 2013
Ponomarenko A., Yury M., Andrey L. et al., Business Informatics 2014
The ability to scale is desirable in computer system as well as business settings. The distributed systems clearly demonstrate this ability and powerfulness to process a very big amount of data. Many system that have distributed architecture like Hadoop file system or distributed torrent tracker are based on the distribute hash table (DHT) which manages ...
Added: October 20, 2014