On -closed sets and their topology.
On -resolvable and almost--resolvable spaces
We continue the study of almost--resolvable spaces beginning in A. Tamariz-Mascar’ua, H. Villegas-Rodr’ıguez, Spaces of continuous functions, box products and almost--resoluble spaces, Comment. Math. Univ. Carolin. 43 (2002), no. 4, 687–705. We prove in ZFC: (1) every crowded space with countable tightness and every space with -weight is hereditarily almost--resolvable, (2) every crowded paracompact space which is the closed preimage of a crowded Fréchet space in such a way that the...
One folkloristic lemma on cardinal reflections in Unif
One-point compactification on convergence spaces.
One-point compactifications of intuitionistic locally compact spaces
Onto Gelfand maps : appendix
Open and closed mappings and compactification
Open covers and infinitary operations in -rings
Open maps do not preserve Whyburn property
We show that a (weakly) Whyburn space may be mapped continuously via an open map onto a non (weakly) Whyburn space . This fact may happen even between topological groups and , a homomorphism, Whyburn and not even weakly Whyburn.
Open subspaces of countable dense homogeneous spaces
We construct a completely regular space which is connected, locally connected and countable dense homogeneous but not strongly locally homogeneous. The space has an open subset which has a unique cut-point. We use the construction of a -diffeomorphism of the plane which takes one countable dense set to another.
Openly factorizable spaces and compact extensions of topological semigroups
We prove that the semigroup operation of a topological semigroup extends to a continuous semigroup operation on its Stone-Čech compactification provided is a pseudocompact openly factorizable space, which means that each map to a second countable space can be written as the composition of an open map onto a second countable space and a map . We present a spectral characterization of openly factorizable spaces and establish some properties of such spaces.
Opérations de Hausdorff itérées et réunions croissantes de compacts
In this paper, motivated by questions in Harmonic Analysis, we study the operation of (countable) increasing union, and show it is not idempotent: iterations are needed in general to obtain the closure of a class under this operation. Increasing union is a particular Hausdorff operation, and we present the combinatorial tools which allow to study the power of various Hausdorff operations, and of their iterates. Besides countable increasing union, we study in detail a related Hausdorff operation,...
Operation-separation axioms in bitopological spaces.
Operator compactification of topological spaces.
Operators associated to a topology over a set and related notions.
Order intervals in . Compactness, coincidence of topologies, metrizability
Let be a compact space and let be the Banach lattice of real-valued continuous functions on . We establish eleven conditions equivalent to the strong compactness of the order interval in , including the following ones: (i) consists of isolated points of ; (ii) is pointwise compact; (iii) is weakly compact; (iv) the strong topology and that of pointwise convergence coincide on ; (v) the strong and weak topologies coincide on . Moreover, the weak topology and that of pointwise convergence...
Ordered Cauchy spaces.
Ordered compactification of totally ordered spaces.
Ordered compactifications and families of maps.
Ordered spaces and quasi-uniformities on spaces of continuous order-preserving functions.
In this paper we introduce and investigate the notions of point open order topology, compact open order topology, the order topology of quasi-uniform pointwise convergence and the order topology of quasi-uniform convergence on compacta. We consider the functorial correspondence between function spaces in the categories of topological spaces, bitopological spaces and ordered topological spaces. We obtain extensions to the topological ordered case of classical topological results on function spaces....