Fixed point free maps of a closed ball with small measures of noncompactness (Q5944980)

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scientific article; zbMATH DE number 1655773
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Fixed point free maps of a closed ball with small measures of noncompactness
scientific article; zbMATH DE number 1655773

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    Fixed point free maps of a closed ball with small measures of noncompactness (English)
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    27 October 2002
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    It is proved that in all infinite-dimensional normed spaces there exist fixed point free continuous maps of the closed unit ball into itself whose measure of noncompactness is not greater than 2. More precisely, this is shown for Kuratowski measure of noncompactness, Hausdorff measure of noncompactness and lattice (separation) measure of noncompactness. For a large class of spaces containing e.g. separable and Hilbert spaces it is proved that there are such maps whose Hausdorff measure of noncompactness attains the best possible bound 1.
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    measure of noncompactness
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    fixed point
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    condensing operator
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