排序方式: 共有5条查询结果,搜索用时 125 毫秒
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Robert F. Brown 《Journal of Fixed Point Theory and Applications》2008,4(2):183-201
The Nielsen number for n-valued multimaps, defined by Schirmer, has been calculated only for the circle. A concept of n-valued fiber map on the total space of a fibration is introduced. A formula for the Nielsen numbers of n-valued fiber maps of fibrations over the circle reduces the calculation to the computation of Nielsen numbers of single-valued
maps. If the fibration is orientable, the product formula for single-valued fiber maps fails to generalize, but a “semi-product
formula" is obtained. In this way, the class of n-valued multimaps for which the Nielsen number can be computed is substantially enlarged.
Dedicated, with gratitude, to Felix Browder who, long ago, encouraged and supported a young topologist’s interest in fixed
point theory 相似文献
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In this paper, a better admissible class B+ is introduced and a new fixed point theorem for better admissible multimap is proved on abstract convex spaces. As a consequence, we deduce a new fixed point theorem on abstract convex Φ-spaces. Our main results generalize some recent work due to Lassonde, Kakutani, Browder, and Park. 相似文献
3.
Jean-Paul Penot 《Set-Valued Analysis》2008,16(4):429-442
We introduce a notion of continuity for multimaps (or set-valued maps) which is mild. It encompasses both lower semicontinuity
and upper semicontinuity. We give characterizations and we consider some permanence properties. This notion can be used for
various purposes. In particular, it is used for continuity properties of subdifferentials and of value functions in parametrized
optimization problems. We also prove an approximate selection theorem.
相似文献
4.
Sehie Park 《Topology and its Applications》2008,155(8):861-870
Applying some of Ernest Michael's selection theorems, from recent fixed point theorems on u.s.c. multimaps, we deduce generalizations of the classical Bolzano theorem, several fixed point theorems on multimaps defined on almost convex sets, almost fixed point theorems, coincidence theorems, and collectively fixed point theorems. These results are related mainly to Michael maps, that is, l.s.c. multimaps having nonempty closed convex values. 相似文献
5.
Sehie Park 《Journal of Mathematical Analysis and Applications》2007,329(1):690-702
We obtain new fixed point theorems on multimaps in the class Bp defined on almost convex subsets of topological vector spaces. Our main results are applied to deduce various fixed point theorems, coincidence theorems, almost fixed point theorems, intersection theorems, and minimax theorems. Consequently, our new results generalize well-known works of Kakutani, Fan, Browder, Himmelberg, Lassonde, and others. 相似文献
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