A note on my paper "Notes on compact semigroups with identity".
In this paper, it is proved that a first-countable paratopological group has a regular -diagonal, which gives an affirmative answer to Arhangel’skii and Burke’s question [Spaces with a regular -diagonal, Topology Appl. 153 (2006), 1917–1929]. If is a symmetrizable paratopological group, then is a developable space. We also discuss copies of and of in paratopological groups and generalize some Nyikos [Metrizability and the Fréchet-Urysohn property in topological groups, Proc. Amer. Math....
Let G be a paratopological group. Then G is said to be pseudobounded (resp. ω-pseudobounded) if for every neighbourhood V of the identity e in G, there exists a natural number n such that G = Vn (resp.we have G = ∪ n∈N Vn). We show that every feebly compact (2-pseudocompact) pseudobounded (ω-pseudobounded) premeager paratopological group is a topological group. Also,we prove that if G is a totally ω-pseudobounded paratopological group such that G is a Lusin space, then is G a topological group....
The proofs of Theorems 2.1, 2.2 and 2.3 from [Olatinwo M.O., Some results on multi-valued weakly jungck mappings in b-metric space, Cent. Eur. J. Math., 2008, 6(4), 610–621] base on faulty evaluations. We give here correct but weaker versions of these theorems.
The centralizer of a semisimple isometric extension of a minimal flow is described.
In a series of papers, Bandt and the author have given a symbolic and topological description of locally connected quadratic Julia sets by use of special closed equivalence relations on the circle called Julia equivalences. These equivalence relations reflect the landing behaviour of external rays in the case of local connectivity, and do not apply completely if a Julia set is connected but fails to be locally connected. However, rational external rays land also in the general case. The present...
In this note we first give a summary that on property of a remainder of a non-locally compact topological group in a compactification makes the remainder and the topological group all separable and metrizable. If a non-locally compact topological group has a compactification such that the remainder of belongs to , then and are separable and metrizable, where is a class of spaces which satisfies the following conditions: (1) if , then every compact subset of the space is a...
Using Tsirelson’s well-known example of a Banach space which does not contain a copy of or , for p ≥ 1, we construct a simple Borel ideal such that the Borel cardinalities of the quotient spaces and are incomparable, where is the summable ideal of all sets A ⊆ ℕ such that . This disproves a “trichotomy” conjecture for Borel ideals proposed by Kechris and Mazur.
Let denote the phase space of the universal minimal dynamical system for a group . Our aim is to show that is homeomorphic to the absolute of , whenever is a countable Abelian group.