| 书目名称 | Measures of Noncompactness and Condensing Operators | | 编辑 | R. R. Akhmerov,M. I. Kamenskii,B. N. Sadovskii | | 视频video | | | 丛书名称 | Operator Theory: Advances and Applications | | 图书封面 |  | | 描述 | A condensing (or densifying) operator is a mapping under which the image of any set is in a certain sense more compact than the set itself. The degree of noncompactness of a set is measured by means of functions called measures of noncompactness. The contractive maps and the compact maps [i.e., in this Introduction, the maps that send any bounded set into a relatively compact one; in the main text the term "compact" will be reserved for the operators that, in addition to having this property, are continuous, i.e., in the authors‘ terminology, for the completely continuous operators] are condensing. For contractive maps one can take as measure of noncompactness the diameter of a set, while for compact maps can take the indicator function of a family of non-relatively com pact sets. The operators of the form F( x) = G( x, x), where G is contractive in the first argument and compact in the second, are also condensing with respect to some natural measures of noncompactness. The linear condensing operators are characterized by the fact that almost all of their spectrum is included in a disc of radius smaller than one. The examples given above show that condensing operators are a suffic | | 出版日期 | Book 1992 | | 关键词 | addition; character; compactness; equation; form; function; functional; functional analysis; functions; integ | | 版次 | 1 | | doi | https://doi.org/10.1007/978-3-0348-5727-7 | | isbn_softcover | 978-3-0348-5729-1 | | isbn_ebook | 978-3-0348-5727-7Series ISSN 0255-0156 Series E-ISSN 2296-4878 | | issn_series | 0255-0156 | | copyright | Springer Basel AG 1992 |
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发表于 2025-3-21 16:47:42
