A -continuum is metrizable if and only if it admits a Whitney map for .
A characterization of dendroids by the n-connectedness of the Whitney levels
Let X be a continuum. Let C(X) denote the hyperspace of all subcontinua of X. In this paper we prove that the following assertions are equivalent: (a) X is a dendroid, (b) each positive Whitney level in C(X) is 2-connected, and (c) each positive Whitney level in C(X) is ∞-connected (n-connected for each n ≥ 0).
A continuum such that is not continuously homogeneous
A metric continuum is said to be continuously homogeneous provided that for every two points there exists a continuous surjective function such that . Answering a question by W.J. Charatonik and Z. Garncarek, in this paper we show a continuum such that the hyperspace of subcontinua of , , is not continuously homogeneous.
A decomposition theorem for a class of continua for which the set function T is continuous
We prove a decomposition theorem for a class of continua for which F. B.. Jones's set function 𝓣 is continuous. This gives a partial answer to a question of D. Bellamy.
A functional representation of the hyperspace monad
A functional representation of the hyperspace monad, based on the semilattice structure of function space, is constructed.
A generalization of boundedly compact metric spaces
A metric space is called a space provided each continuous function on into a metric target space is uniformly continuous. We introduce a class of metric spaces that play, relative to the boundedly compact metric spaces, the same role that spaces play relative to the compact metric spaces.
A hit-and-miss topology for , Cₙ(X) and Fₙ(X)
A hit-and-miss topology () is defined for the hyperspaces , Cₙ(X) and Fₙ(X) of a continuum X. We study the relationship between and the Vietoris topology and we find conditions on X for which these topologies are equivalent.
A maximal chain approach to topology and order.
A new approach to a hyperspace theory.
A new hyperspace topology and the study of the function space -
A note on separability of the Fell-hyperspace topology
A Property Between Compact and Strongly Countably Compact
A Ramsey theorem for polyadic spaces
A polyadic space is a Hausdorff continuous image of some power of the one-point compactification of a discrete space. We prove a Ramsey-like property for polyadic spaces which for Boolean spaces can be stated as follows: every uncountable clopen collection contains an uncountable subcollection which is either linked or disjoint. One corollary is that is not a universal preimage for uniform Eberlein compact spaces of weight at most κ, thus answering a question of Y. Benyamini, M. Rudin and M. Wage....
A Theorem On Spaces 2X With The Compact-Open Topology
A theorem on spaces 2x with the compact-open topology.
About -covers and -networks on the Vietoris hyperspace
We study some generalized metric properties on the hyperspace of finite subsets of a space endowed with the Vietoris topology. We prove that has a point-star network consisting of (countable) -covers if and only if so does . Moreover, has a sequence of -covers with property which is a point-star network if and only if so does , where is one of the following properties: point-finite, point-countable, compact-finite, compact-countable, locally finite, locally countable. On the other...
Absolute n-fold hyperspace suspensions
The notion of an absolute n-fold hyperspace suspension is introduced. It is proved that these hyperspaces are unicoherent Peano continua and are dimensionally homogeneous. It is shown that the 2-sphere is the only finite-dimensional absolute 1-fold hyperspace suspension. Furthermore, it is shown that there are only two possible finite-dimensional absolute n-fold hyperspace suspensions for each n ≥ 3 and none when n = 2. Finally, it is shown that infinite-dimensional absolute n-fold hyperspace suspensions...
Affine group acting on hyperspaces of compact convex subsets of ℝⁿ
For every n ≥ 2, let cc(ℝⁿ) denote the hyperspace of all nonempty compact convex subsets of the Euclidean space ℝⁿ endowed with the Hausdorff metric topology. Let cb(ℝⁿ) be the subset of cc(ℝⁿ) consisting of all compact convex bodies. In this paper we discover several fundamental properties of the natural action of the affine group Aff(n) on cb(ℝⁿ). We prove that the space E(n) of all n-dimensional ellipsoids is an Aff(n)-equivariant retract of cb(ℝⁿ). This is applied to show that cb(ℝⁿ) is homeomorphic...
Algebra in the superextensions of twinic groups [Book]
An answer to a question on hyperspaces