EuDML | Browse

The paper presents new quasicontinuous selection theorem for continuous multifunctions $F X ⟶ ℝ$ with closed values, $X$ being an arbitrary topological space. It is known that for $2^{ℝ}$ with the Vietoris topology there is no continuous selection. The result presented here enables us to show that there exists a quasicontinuous and upper $〈$ lower $〉$ -semicontinuous selection for this space. Moreover, one can construct a selection whose set of points of discontinuity is nowhere dense.

Existence of solutions to second order ordinary differential equations having finite limits at $\pm$ infinity.

Avramescu, Cezar, Vladimirescu, Cristian (2004)

Electronic Journal of Differential Equations (EJDE) [electronic only]

Exotic ANR's via null decompositions of Hilbert cube manifolds

S. Singh (1985)

Fundamenta Mathematicae

Expansion of $α$ -open sets and decomposition of $α$ -continuous mappings.

Rajamani, M., Bagyalakshmi, K. (2005)

International Journal of Mathematics and Mathematical Sciences

Exponentiability in homotopy slices of TOP and pseudo-slices of CAT.

Niefield, Susan (2007)

Theory and Applications of Categories [electronic only]

Exponentiability of perfect maps: Four approaches.

Niefield, Susan (2002)

Theory and Applications of Categories [electronic only]

Exponentiable morphisms: Posets, spaces, locales, and Grothendieck toposes.

Niefield, Susan (2001)

Theory and Applications of Categories [electronic only]

Exponential domination in function spaces

Vladimir Vladimirovich Tkachuk (2020)

Commentationes Mathematicae Universitatis Carolinae

Given a Tychonoff space $X$ and an infinite cardinal $κ$ , we prove that exponential $κ$ -domination in $X$ is equivalent to exponential $κ$ -cofinality of $C_{p} (X)$ . On the other hand, exponential $κ$ -cofinality of $X$ is equivalent to exponential $κ$ -domination in $C_{p} (X)$ . We show that every exponentially $κ$ -cofinal space $X$ has a $κ^{+}$ -small diagonal; besides, if $X$ is $κ$ -stable, then $n w (X) \leq κ$ . In particular, any compact exponentially $κ$ -cofinal space has weight not exceeding $κ$ . We also establish that any exponentially $κ$ -cofinal space $X$ with...

Exponential law for uniformly continous proper maps.

R. Ayala, E. Dominguez, A. Quintero (1988)

Publicacions Matemàtiques

The purpose of this note is to prove the exponential law for uniformly continuous proper maps.

Exponential separability is preserved by some products

Vladimir Vladimirovich Tkachuk (2022)

Commentationes Mathematicae Universitatis Carolinae

We show that exponential separability is an inverse invariant of closed maps with countably compact exponentially separable fibers. This implies that it is preserved by products with a scattered compact factor and in the products of sequential countably compact spaces. We also provide an example of a $σ$ -compact crowded space in which all countable subspaces are scattered. If $X$ is a Lindelöf space and every $Y \subset X$ with $| Y | \leq 2^{ω_{1}}$ is scattered, then $X$ is functionally countable; if every $Y \subset X$ with $| Y | \leq 2^{𝔠}$ is scattered, then...

Extended Bochner Measurable Selectors.

Roger W. Hansell (1987)

Mathematische Annalen

Extended topology: continuity - I

Hammer, Preston C. (1964)

Portugaliae mathematica

Extended topology: perfect sets

Hammer, Preston C. (1964)

Portugaliae mathematica

Extended Topology: Structure of Isotonic Functions.

Preston C. Hammer (1964)

Journal für die reine und angewandte Mathematik

Extenders for vector-valued functions

Iryna Banakh, Taras Banakh, Kaori Yamazaki (2009)

Studia Mathematica

Given a subset A of a topological space X, a locally convex space Y, and a family ℂ of subsets of Y we study the problem of the existence of a linear ℂ-extender $u : C_{\infty} (A, Y) \to C_{\infty} (X, Y)$ , which is a linear operator extending bounded continuous functions f: A → C ⊂ Y, C ∈ ℂ, to bounded continuous functions f̅ = u(f): X → C ⊂ Y. Two necessary conditions for the existence of such an extender are found in terms of a topological game, which is a modification of the classical strong Choquet game. The results obtained allow us...

Currently displaying 61 – 80 of 116

Previous Page 4 Next