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Products of Fréchet spaces
Olšák, Miroslav ; Simon, Petr (advisor) ; Chodounský, David (referee)
The article gives a constructions of k-tuples of topological spaces such that the product of the k-tuple is not Frchet-Urysohn but all smaller subproducts are. The construction uses almost disjoint systems. The article repeats the construction by Petr Simon of two such compact spaces. To achieve more dimensional example there are generalized terms of AD systems. The example is constructed under the assumption of existence of a strong completely separable MAD system. It is then constructed under the assumption s ≤ b where s is the splitting number and b is the bounding number.
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Topologies generated by adding single points
Bartoš, Adam ; Simon, Petr (advisor)
We define a general notion of closure scheme to systematically study the classes of Fréchet, sequetial, (pseudo)radial, (weakly) (discretely) Whyburn, and (weakly) discretely generated spaces. First, several general propositions on closure schemes and preservation of induced properties under topological constructions are proved and later applied when we systematically summarize the properties of the classes mentioned above. Next, we focus on a detailed overview of inclusions between the classes in the general case, in the case of Hausdorff spaces, and under additional conditions like compactness and countable compactness. Valid inclusions between the classes are summarized in well arranged diagrams, invalid inclusions are demonstrated by several counterexamples.
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Products of Fréchet spaces
Olšák, Miroslav ; Simon, Petr (advisor) ; Chodounský, David (referee)
The article gives a constructions of k-tuples of topological spaces such that the product of the k-tuple is not Frchet-Urysohn but all smaller subproducts are. The construction uses almost disjoint systems. The article repeats the construction by Petr Simon of two such compact spaces. To achieve more dimensional example there are generalized terms of AD systems. The example is constructed under the assumption of existence of a strong completely separable MAD system. It is then constructed under the assumption s ≤ b where s is the splitting number and b is the bounding number.
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Topologies generated by adding single points
Bartoš, Adam ; Simon, Petr (advisor)
We define a general notion of closure scheme to systematically study the classes of Fréchet, sequetial, (pseudo)radial, (weakly) (discretely) Whyburn, and (weakly) discretely generated spaces. First, several general propositions on closure schemes and preservation of induced properties under topological constructions are proved and later applied when we systematically summarize the properties of the classes mentioned above. Next, we focus on a detailed overview of inclusions between the classes in the general case, in the case of Hausdorff spaces, and under additional conditions like compactness and countable compactness. Valid inclusions between the classes are summarized in well arranged diagrams, invalid inclusions are demonstrated by several counterexamples.
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Topologies generated by adding single points
Bartoš, Adam ; Simon, Petr (advisor) ; Hušek, Miroslav (referee)
We define a general notion of closure scheme to systematically study the classes of Fréchet, sequetial, (pseudo)radial, (weakly) (discretely) Whyburn, and (weakly) discretely generated spaces. First, several general propositions on closure schemes and preservation of induced properties under topological constructions are proved and later applied when we systematically summarize the properties of the classes mentioned above. Next, we focus on a detailed overview of inclusions between the classes in the general case, in the case of Hausdorff spaces, and under additional conditions like compactness and countable compactness. Valid inclusions between the classes are summarized in well arranged diagrams, invalid inclusions are demonstrated by several counterexamples.
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