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Related papers: Construction of functions with given cluster sets

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We study linear and algebraic structures in sets of bounded holomorphic functions on the ball which have large cluster sets at every possible point (i.e., every point on the sphere in several complex variables and every point of the closed…

Functional Analysis · Mathematics 2019-06-07 Thiago R. Alves , Daniel Carando

Let $X$ and $M$ be a topological space and metric space, respectively. If $C(X,M)$ denotes the set of all continuous functions from X to M, we say that a subset $Y$ of $X$ is an \emph{$M$-interpolation set} if given any function $g\in M^Y$…

General Topology · Mathematics 2018-04-03 María V. Ferrer , Salvador Hernández , Luis Tárrega

Assume that $\mathcal{P}$ is a topological property of a space $X$, then we say that $X$ is {\it dense-$\mathcal{P}$} if each dense subset of $X$ has the property $\mathcal{P}$. In this paper, we mainly discuss dense subsets of a space $X$,…

General Topology · Mathematics 2023-04-10 Fucai Lin , Qiyun Wu

We give a characterization of countable discrete subspace $A$ of a topological space $X$ such that there exists a (linear) continuous mapping $\varphi:C_p^*(A)\to C_p(X)$ with $\varphi(y)|_A=y$ for every $y\in C_p^*(A)$. Using this…

General Topology · Mathematics 2016-04-22 V. Mykhaylyuk

Let $D^2 \subset C$ be a closed two-dimensional disk and $f:D^2 \to R$ be a continuous function such that a restriction of $f$ to $\partial D^2$ is a continuous function with a finite number of local extrema and $f$ has a finite number of…

General Topology · Mathematics 2009-10-20 Yevgen Polulyakh , Iryna Yurchuk

Let $Y$ be a metrizable space containing at least two points, and let $X$ be a $Y_{\mathcal{I}}$-Tychonoff space for some ideal $\mathcal{I}$ of compact sets of $X$. Denote by $C_{\mathcal{I}}(X,Y)$ the space of continuous functions from…

General Topology · Mathematics 2020-04-14 Saak Gabriyelyan , Alexander V. Osipov

Let $X$ be a Borel subset of the Cantor set \textbf{C} of additive or multiplicative class ${\alpha},$ and $f: X \to Y$ be a continuous function with compact preimages of points onto $Y \subset \textbf{C}.$ If the image $f(U)$ of every…

General Topology · Mathematics 2011-02-17 Alexey Ostrovsky

Given a domain of holomorphy $D$ in $\mathbb{C}^N$, $N\geq 2$, we show that the set of holomorphic functions in $D$ whose cluster sets along any finite length paths to the boundary of $D$ is maximal, is residual, densely lineable and…

Complex Variables · Mathematics 2020-03-04 Stéphane Charpentier , Łukasz Kosiński

A map $f:X\to Y$ between topological spaces is defined to be {\em scatteredly continuous} if for each subspace $A\subset X$ the restriction $f|A$ has a point of continuity. We show that for a function $f:X\to Y$ from a perfectly paracompact…

Geometric Topology · Mathematics 2011-10-11 T. Banakh , B. Bokalo

Let $X,X_1,X_2,\ldots$ be i.i.d. mean zero random vectors with values in a separable Banach space $B$, $S_n=X_1+\cdots+X_n$ for $n\ge1$, and assume $\{c_n:n\ge1\}$ is a suitably regular sequence of constants. Furthermore, let…

Probability · Mathematics 2014-03-28 Uwe Einmahl , Jim Kuelbs

We investigate existence and uniqueness of maximal plurisubharmonic functions on bounded domains with boundary data that are not assumed to be continuous or bounded. The result is applied to approximate (possibly unbounded from above)…

Complex Variables · Mathematics 2025-09-16 N. Q. Dieu , T. V. Long , T. D. Hieu

We consider two natural topologies on the space $S(X\times Y,Z)$ of all separately continuous functions defined on the product of two topological spaces $X$ and $Y$ and ranged into a topological or metric space $X$. These topologies are the…

General Topology · Mathematics 2025-01-03 Oleksandr Maslyuchenko , Vadym Myronyk , Roman Ivasiuk

It is known that for $X$ a nowhere locally compact metric space, the set of bounded continuous, nowhere locally uniformly continuous real-valued functions on $X$ contains a dense $G_\delta$ set in the space $C_b(X)$ of all bounded…

General Topology · Mathematics 2021-05-21 Alexander J. Izzo

We introduce a continuous domain for function spaces over topological spaces which are not core-compact. Notable examples of such topological spaces include the real line with the upper limit topology, which is used in solution of initial…

Logic in Computer Science · Computer Science 2024-12-18 Amin Farjudian , Achim Jung

We consider the space of real-valued continuously differentiable functions on a compact subset of a euclidean space. We characterize the completeness of this space and prove that the space of restrictions of continuously differentiable…

Classical Analysis and ODEs · Mathematics 2020-06-18 Leonhard Frerick , Laurent Loosveldt , Jochen Wengenroth

This paper studies the C-compact-open topology on the set C(X) of all realvalued continuous functions on a Tychonov space X and compares this topology with several well-known and lesser known topologies. We investigate the properties…

General Topology · Mathematics 2012-01-10 Alexander V. Osipov

We construct a family F of compact and pathwise connected subsets of the Euclidean plane such that (i) the cardinality of F is that of the continuum (and hence extremely large) and (ii) if X,Y are distinct spaces in F then there never…

General Topology · Mathematics 2024-01-29 Gerald Kuba

In this paper we continue the study initiated by Gurariy and Quarta in 2004 on the existence of linear spaces formed, up to the null vector, by continuous functions that attain the maximum only at one point. Inserting a topological flavor…

Functional Analysis · Mathematics 2012-12-19 G. Botelho , D. Cariello , V. V. Fávaro , D. Pellegrino , J. B. Seoane-Sepúlveda

For every affine variety over a global function field, we show that the set of its points with coordinates in an arbitrary rank-one multiplicative subgroup of this function field is topologically dense in the set of its points with…

Number Theory · Mathematics 2016-11-01 Chia-Liang Sun

Let $D$ be the open unit disc in the complex plane. We denote by $\mathbb{C}$ the set of complex numbers and consider any compact set $K$ which is disjoint from $D$ and which also has connected complement. Let $A(K)$ denote all the…

Complex Variables · Mathematics 2015-06-05 Nikos Tsirivas