\(ls\)-Ponomarev-systems and 1-sequence-covering mappings (Q2894166)
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scientific article; zbMATH DE number 6050996
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | \(ls\)-Ponomarev-systems and 1-sequence-covering mappings |
scientific article; zbMATH DE number 6050996 |
Statements
29 June 2012
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\textit{ls}-Ponomarev system
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1-sequence covering
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2-sequence covering
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double point-star \textit{wsn}-cover
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double point-star \textit{so}-cover
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0.9909042
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0.9141934
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0.9086181
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0.8719297
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\(ls\)-Ponomarev-systems and 1-sequence-covering mappings (English)
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A map \(f:X\to Y\) is a 1-sequence covering map (resp. 2-sequence covering map) provided for each \(y\in Y\) there is \(x\in f^{-1}(y)\) (resp. for each \(x\in f^{-1}(y)\)), for each sequence \(\langle y_n\rangle\) converging to \(y\) there is a sequence \(\langle x_n\rangle\) converging to \(x\) with \(x_n\in f^{-1}(y_n)\) for each \(n\). The main result characterises 1- (resp. 2-) sequence covering maps from a locally separable metric space in terms of the author's double point star covers of the range space.
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