Displaying similar documents to “Closed mappings which lower dimension”

On topological classification of complex mappings

Hadi Seyedinejad, Ali Zaghian (2015)

Annales Polonici Mathematici

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We study the topological invariant ϕ of Kwieciński and Tworzewski, particularly beyond the case of mappings with smooth targets. We derive a lower bound for ϕ of a general mapping, which is similarly effective as the upper bound given by Kwieciński and Tworzewski. Some classes of mappings are identified for which the exact value of ϕ can be computed. Also, we prove that the variation of ϕ on the source space of a mapping with a smooth target is semicontinuous in the Zariski topology. ...

There Are No Essential Phantom Mappings from 1-dimensional CW-complexes

Sibe Mardešić (2013)

Bulletin of the Polish Academy of Sciences. Mathematics

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A phantom mapping h from a space Z to a space Y is a mapping whose restrictions to compact subsets are homotopic to constant mappings. If the mapping h is not homotopic to a constant mapping, one speaks of an essential phantom mapping. The definition of (essential) phantom pairs of mappings is analogous. In the study of phantom mappings (phantom pairs of mappings), of primary interest is the case when Z and Y are CW-complexes. In a previous paper it was shown that there are no essential...