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关于正定矩阵一不等式的简单证明 总被引:2,自引:0,他引:2
设A=(aij)是一n阶正定实对称矩阵,本文用代数方法证明了|A|≤a11a22…ann,当且仅当A是对角矩阵时等号成立.且证法简单. 相似文献
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一类P-LAPLACIAN边值问题的多个正解 总被引:3,自引:0,他引:3
基于 Leggett-Williams在锥上的不动点定理研究两点边值问题(φp( u′( t) ) )′+ a( t) f ( u( t) ) =0 t∈ ( 0 ,1 )u′( 0 ) =0 , αu′( 1 ) + u( 1 ) =0其中 α∈ R,a:( 0 ,1 )→ [0 ,+∞ ) ,f :[0 ,+∞ )→ R,p( z) =| z| p- 2 z,获得了保证正解存在的充分条件 相似文献
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给出了以下边值问题正解存在的充分条件,(p(t)u′(t)′ α(t)f(t,u(t))=r(t) t∈(0,1) u(0)=0,au(η)=u(l)其中0<η<1,α>0,应用锥上的不动点定理证明在不同的假设条件下,以上边值问题仅有唯一正解,或有两个正解,或无数个正解. 相似文献
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Opinion dynamics models based on the multi-agent method commonly assume that interactions between individuals in a social network result in changes in their opinions.However,formation of public opinion in a social network is a macroscopic statistical result of opinions of all expressive individuals(corresponding to silent individuals).Therefore,public opinion can be manipulated not only by changing individuals'opinions,but also by changing their states of expression(or silence)which can be interpreted as the phenomenon"spiral of silence"in social psychology.Based on this theory,we establish a"dual opinion climate"model,involving social bots and mass media through a multi-agent method,to describe mechanism for manipulation of public opinion in social networks.We find that both social bots(as local variables)and mass media(as a global variable)can interfere with the formation of public opinion,cause a significant superposition effect when they act in the same direction,and inhibit each other when they act in opposite directions. 相似文献
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本文利用条件概率的定义,由随机变量分布函数的性质,给出一般情形下随机变量条件分布函数的定义,以帮助学生更好地理解随机变量的条件分布函数的概念. 相似文献