Generalized ordered spaces with capacities (Q794320)
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scientific article; zbMATH DE number 3859985
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Generalized ordered spaces with capacities |
scientific article; zbMATH DE number 3859985 |
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Generalized ordered spaces with capacities (English)
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1984
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The authors investigate a notion of capacity in the sense of Shchepin, for the class of generalized ordered topological spaces, GO-spaces. Any GO-space with a capacity is perfect, has a \(G_{\delta}\)-diagonal, so if it is LOTS, then it is metrizable (Shchepin). Moreover, such a space has a \(\sigma\)-discrete dense subset and a dense metrizable subspace. In addition, if it has a point-countable base or \(\delta \theta\)-base then it is metrizable. A capacity for a space X is a family of functions \(\{\epsilon_ x:\) \(x\in X\}\) defined on the family of closed subsets such that: (1) \(\epsilon_ x(F)>0\) iff \(x\in int F\), (2) \(F\subset H\) implies \(\epsilon_ x(F)\leq \epsilon_ x(H),\) (3) for fixed F, the function \(x\mapsto \epsilon_ x(F)\) is continuous, (4) for fixed x, if \(F_ 0\supset F_ 1\supset...\supset F_{\alpha}\supset..., \alpha<\kappa\), then \(\epsilon_ x(\cap F_{\alpha})=\inf_{\alpha<\kappa}\epsilon_ x(F_{\alpha}).\)
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perfect spaces
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metrizability
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point-countable base
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GO-spaces
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