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JOURNALS // Matematicheskii Sbornik // Archive

Mat. Sb. (N.S.), 1988 Volume 136(178), Number 2(6), Pages 292–300 (Mi sm1742)

This article is cited in 9 papers

On the question of the existence of continuous branches of multivalued mappings with nonconvex images in spaces of summable functions

A. I. Bulgakov


Abstract: Let $B$ be a Banach space with norm $\|\cdot\|$, and let $(E,\mathfrak M)$ be a compact topological space with $\sigma$-algebra of measurable sets $\mathfrak M$ on which a nonnegative regular Borel measure $\mu$ is given. Further, let $L_1(E,B)$ be the Banach space of Bochner-integrable functions $u\colon E\to B$, with the norm $\|u\|_{L_1(E,B)}=\int_E\|u(t)\|\,d\mu$, and let $\Phi\colon K\to2^{L_1(E,B)}$ be a multivalued mapping and $P\colon K\to L_1(E,B)$ a single-valued mapping, where $K$ is a compact topological space. Under certain assumptions it is proved that for any $\varepsilon>0$ there exists a continuous mapping $g\colon K\to L_1(E,B)$ such that the following conditions hold for any $x\in K$: $g(x)\in\Phi(x)$, and $\|P(x)-g(x)\|_{L_1(E,B)}<\rho_{L_1(E,B)}[P(x),\Phi(x)]+\varepsilon$, where $\rho_{L_1(E,B)}[\,\cdot\,{,}\,\cdot\,]$ is the distance in $L_1(E,B)$ from a point to a set.
Bibliography: 11 titles.

UDC: 517.965

MSC: Primary 54C65; Secondary 46E30

Received: 13.01.1987


 English version:
Mathematics of the USSR-Sbornik, 1989, 64:1, 295–303

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