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可分商空间 被引量:1
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作者 石峰 《武汉大学学报(自然科学版)》 CSCD 1996年第5期561-566,共6页
考虑无穷维商空间问题,得到一个无穷维Banach空间X具有可分的无穷维商空间的几个充分条件.并且还得到:若X*含有l1,则或者X含有l1。
关键词 可分商空间 Shcauder基 线性算子 巴拿赫空间
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Banach空间可分性及可分商问题
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作者 孙淑芹 刘军 莫智文 《四川师范大学学报(自然科学版)》 CAS CSCD 北大核心 2012年第3期313-317,共5页
可分商问题:是否每一个无限维的Banach空间都有一个无限维的、可分的商空间?这是一个至今都没有完全解决的问题.结合对该问题已有的等价转换条件,在系统研究了Banach空间在范数拓扑,w*拓扑和w拓扑中的可分性质以及讨论了它们之间的相互... 可分商问题:是否每一个无限维的Banach空间都有一个无限维的、可分的商空间?这是一个至今都没有完全解决的问题.结合对该问题已有的等价转换条件,在系统研究了Banach空间在范数拓扑,w*拓扑和w拓扑中的可分性质以及讨论了它们之间的相互关系的基础上,先后得到在一般的Banach空间和经典Banach空间中可分商问题得以肯定回答的充分条件.研究结果一方面充实了Banach空间在3种常用拓扑关于可分的理论内容,另一方面也为可分商问题的进一步解决提供了丰富的理论基础. 展开更多
关键词 BANACH空间 可分 可分商
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Innovation in China: Evidence From the Provincial Data
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作者 Roberta Arbolino 《Chinese Business Review》 2011年第10期855-867,共13页
China has made remarkable gains in industrialization and development. In the last years, in order to ensure the sustainability of its economic and social development, China gave more importance to the innovativeness o... China has made remarkable gains in industrialization and development. In the last years, in order to ensure the sustainability of its economic and social development, China gave more importance to the innovativeness of business enterprises. In the domestic arena, the sustainability of the growth model that China has followed over the past decades has been criticized because of its excessive reliance on capital and resources as opposed to knowledge and innovation. In 2006, that transformation has been at the centre of the government's "scientific development strategy". Today, in fact, innovation and promotion of entrepreneurship are essential conditions for competitiveness of firms and nations, for the long-term growth and, therefore, for the economy as a whole. This paper investigates the level of potential innovation reached in China in 2008 through a disaggregated analysis, evaluating the production capacity of the Chinese provinces. "Innovation" has been widely studied by economic literature, specially with reference to the output. In this paper, we will refer to the European Innovation Scoreboard (EIS) index, to measure the progress of innovation, which represents the skill to innovate of a territory, but not the achieved innovation. First, we will propose some methodological changes of this method, that allows to obtained a ranking, in order to better understand the results reached by the Chinese provinces; Then we will test a different methodology in order to measure the level of potential innovation overcoming the limits of current practice--from a composite index obtained through a mean of disaggregated indices to multivariate analysis. 展开更多
关键词 DEVELOPMENT INNOVATION multivariate analysis
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Almost all points on the real axis can be original points of shock waves 被引量:1
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作者 LI Bang-He 《Science China Mathematics》 SCIE 2011年第1期1-8,共8页
For a conservation law with convex condition and initial data in L∞(R), it had been commonly believed that the number of discontinuity lines (or shock waves) of the solution is at most countable since Theorem 1 in Ol... For a conservation law with convex condition and initial data in L∞(R), it had been commonly believed that the number of discontinuity lines (or shock waves) of the solution is at most countable since Theorem 1 in Oleinik's seminal paper published in 1956 asserted this fact. In 1977, the author gave an example to show that there is an initial data in C∞(R) ∩ L∞(R) such that the number of shock waves is uncountable. And in 1980, he gave an example to show that there is an initial data in C(R)∩L∞(R) such that the measure of original points of shock waves on the real axis is positive. In this paper, he proves further that the set consisting of initial data in C(R) ∩ L∞(R) with the property: almost all points on the real axis are original points of shock waves, is dense in C(R) ∩ L∞(R). All these results show that Oleinik's assertion on the countability of discontinuity lines is wrong. 展开更多
关键词 conservation law shock wave original points on real axis
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Rationality of quotients by linear actions of affine groups
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作者 BOGOMOLOV Fedor BHNING Christian GRAF VON BOTHMER Hans-Christian 《Science China Mathematics》 SCIE 2011年第8期1521-1532,共12页
LetG = SLn(C)Cn be the (special) affine group. In this paper we study the representation theory of G and in particular the question of rationality for V/G, where V is a generically free G-representation. We show that ... LetG = SLn(C)Cn be the (special) affine group. In this paper we study the representation theory of G and in particular the question of rationality for V/G, where V is a generically free G-representation. We show that the answer to this question is positive (Theorem 6.1) if the dimension of V is sufficiently large and V is indecomposable. We explicitly characterize two-step extensions 0 → S → V → Q → 0, with completely reducible S and Q, whose rationality cannot be obtained by the methods presented here (Theorem 5.3). 展开更多
关键词 RATIONALITY linear group quotients affine groups
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