On the dimension modulo classes of topological spaces and free topological groups.
On the dimension of increments of Tychonoff spaces
On the dimension of ordered spaces.
On the dimension of remainders in extensions of product spaces
On the dimension of the space of ℝ-places of certain rational function fields
We prove that for every n ∈ ℕ the space M(K(x 1, …, x n) of ℝ-places of the field K(x 1, …, x n) of rational functions of n variables with coefficients in a totally Archimedean field K has the topological covering dimension dimM(K(x 1, …, x n)) ≤ n. For n = 2 the space M(K(x 1, x 2)) has covering and integral dimensions dimM(K(x 1, x 2)) = dimℤ M(K(x 1, x 2)) = 2 and the cohomological dimension dimG M(K(x 1, x 2)) = 1 for any Abelian 2-divisible coefficient group G.
On the disjoint (0,N)-cells property for homogeneous ANR's
A metric space (X,ϱ) satisfies the disjoint (0,n)-cells property provided for each point x ∈ X, any map f of the n-cell into X and for each ε > 0 there exist a point y ∈ X and a map such that ϱ(x,y) < ε, and . It is proved that each homogeneous locally compact ANR of dimension >2 has the disjoint (0,2)-cells property. If dimX = n > 0, X has the disjoint (0,n-1)-cells property and X is a locally compact -space then local homologies satisfy for k < n and Hn(X,X-x) ≠ 0.
On the division by Rn.
On the equivalence of certain coincidence theorems and fixed point theorems
On the existence of arcs in rational curves
On the existence of means on solenoids.
On the fundamental dimension of the Cartesian product of compacta with the fundamental dimension 2
On the Hausdorff Dimension of Topological Subspaces
It is shown that every Polish space X with admits a compact subspace Y such that where and denote the topological and Hausdorff dimensions, respectively.
On the homology of the Harmonic Archipelago
We calculate the singular homology and Čech cohomology groups of the Harmonic Archipelago. As a corollary, we prove that this space is not homotopy equivalent to the Griffiths space. This is interesting in view of Eda’s proof that the first singular homology groups of these spaces are isomorphic.
On the hyperspace
Let be a continuum and a positive integer. Let be the hyperspace of all nonempty closed subsets of with at most components, endowed with the Hausdorff metric. For compact subset of , define the hyperspace . In this paper, we consider the hyperspace , which can be a tool to study the space . We study this hyperspace in the class of finite graphs and in general, we prove some properties such as: aposyndesis, local connectedness, arcwise disconnectedness, and contractibility.
On the hyperspace of subcontinua of a finite graph I
On the hyperspace of subcontinua of a finite graph, II
On the hyperspaces of hereditarily indecomposable continua
On the hyperspaces of snake-like and circle-like continua
On the inequivalence of the Borsuk and the H-shape theories for arbitrary metric spaces
On the lattice of convexly compatible topologies on a partially ordered set