Advances in Pure Mathematics

Volume 9, Issue 6 (June 2019)

ISSN Print: 2160-0368   ISSN Online: 2160-0384

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Almost Injective Mappings of Totally Bounded Metric Spaces into Finite Dimensional Euclidean Spaces

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DOI: 10.4236/apm.2019.96028    647 Downloads   1,316 Views  Citations
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ABSTRACT

Let χ= be a metric space and let ε be a positive real number. Then a function f: X→Y is defined to be an ε-map if and only if for all yY, the diameter of f-1(y) is at most ε. In Theorem 10 we will give a new proof for the following well known fact: if χ is totally bounded, then for all ε there exists a finite number n and a continuous ε-map fε: X→Rn (here Rn is the usual n-dimensional Euclidean space endowed with the Euclidean metric). If ε is “small”, then fε is “almost injective”; and still exists even if χ has infinite covering dimension (in this case, n depends on ε, of course). Contrary to the known proofs, our proof technique is effective in the sense, that it allows establishing estimations for n in terms of ε and structural properties of χ.

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Sági, G. (2019) Almost Injective Mappings of Totally Bounded Metric Spaces into Finite Dimensional Euclidean Spaces. Advances in Pure Mathematics, 9, 555-566. doi: 10.4236/apm.2019.96028.

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