On inverses of $\delta$-convex mappings
Commentationes Mathematicae Universitatis Carolinae, Tome 42 (2001) no. 2, pp. 281-297
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In the first part of this paper, we prove that in a sense the class of bi-Lipschitz $\delta$-convex mappings, whose inverses are locally $\delta$-convex, is stable under finite-dimensional $\delta$-convex perturbations. In the second part, we construct two $\delta$-convex mappings from $\ell_1$ onto $\ell_1$, which are both bi-Lipschitz and their inverses are nowhere locally $\delta$-convex. The second mapping, whose construction is more complicated, has an invertible strict derivative at $0$. These mappings show that for (locally) $\delta$-convex mappings an infinite-dimensional analogue of the finite-dimensional theorem about $\delta$-convexity of inverse mappings (proved in [7]) cannot hold in general (the case of $\ell_2$ is still open) and answer three questions posed in [7].
Classification :
46G99, 47H99, 58C20, 90C48
Keywords: delta-convex mappings; strict differentiability; normed linear spaces
Keywords: delta-convex mappings; strict differentiability; normed linear spaces
@article{CMUC_2001__42_2_a5,
author = {Duda, Jakub},
title = {On inverses of $\delta$-convex mappings},
journal = {Commentationes Mathematicae Universitatis Carolinae},
pages = {281--297},
publisher = {mathdoc},
volume = {42},
number = {2},
year = {2001},
mrnumber = {1832147},
zbl = {1053.47522},
language = {en},
url = {http://geodesic.mathdoc.fr/item/CMUC_2001__42_2_a5/}
}
Duda, Jakub. On inverses of $\delta$-convex mappings. Commentationes Mathematicae Universitatis Carolinae, Tome 42 (2001) no. 2, pp. 281-297. http://geodesic.mathdoc.fr/item/CMUC_2001__42_2_a5/