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A note on the paper ``Smoothness and the property of Kelley''

Gerardo Acosta, Álgebra Aguilar-Martínez (2007)

Commentationes Mathematicae Universitatis Carolinae

Let X be a continuum. In Proposition 31 of J.J. Charatonik and W.J. Charatonik, Smoothness and the property of Kelley, Comment. Math. Univ. Carolin. 41 (2000), no. 1, 123–132, it is claimed that L ( X ) = p X S ( p ) , where L ( X ) is the set of points at which X is locally connected and, for p X , a S ( p ) if and only if X is smooth at p with respect to a . In this paper we show that such equality is incorrect and that the correct equality is P ( X ) = p X S ( p ) , where P ( X ) is the set of points at which X is connected im kleinen. We also use the correct...

A note on topology of Z -continuous posets

Venu G. Menon (1996)

Commentationes Mathematicae Universitatis Carolinae

Z -continuous posets are common generalizations of continuous posets, completely distributive lattices, and unique factorization posets. Though the algebraic properties of Z -continuous posets had been studied by several authors, the topological properties are rather unknown. In this short note an intrinsic topology on a Z -continuous poset is defined and its properties are explored.

A note on transitively D -spaces

Liang-Xue Peng (2011)

Czechoslovak Mathematical Journal

In this note, we show that if for any transitive neighborhood assignment φ for X there is a point-countable refinement such that for any non-closed subset A of X there is some V such that | V A | ω , then X is transitively D . As a corollary, if X is a sequential space and has a point-countable w c s * -network then X is transitively D , and hence if X is a Hausdorff k -space and has a point-countable k -network, then X is transitively D . We prove that if X is a countably compact sequential space and has a point-countable...

A relatively free topological group that is not varietal free

Vladimir Pestov, Dmitri Shakhmatov (1998)

Colloquium Mathematicae

Answering a 1982 question of Sidney A. Morris, we construct a topological group G and a subspace X such that (i) G is algebraically free over X, (ii) G is relatively free over X, that is, every continuous mapping from X to G extends to a unique continuous endomorphism of G, and (iii) G is not a varietal free topological group on X in any variety of topological groups.

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