目的如果Si (i = 1,…,n)是密度矩阵,π = { πi }i=1^n是一个概率分布,并且A(0) ≡ ∑i=1nπiiSi^1/2是可逆的,那么Tr[{∑j=1nπjSj(log Sj)^2}-A(0)^-1{∑j=1nπjH(Sj)}^2]≥0,其中H(x) =- xlog x ,这是Yanagi证明的不等式的一个推广。方法利用Caushy—Schwarz不等式,Jensen's不等式和迹的一些性质来证明。结果这些涉及矩阵和对数的不等式给出了由Yanagi提出的开放问题的部分解答。结论因为这些结论仅仅是特例,所以在此基础上可做进一步的研究。
Aim It is proved that if Si (i = 1,…,n) be density matrices, π = { πi }i=1^n be a probability distribution and A(0) ≡ ∑i=1nπiiSi^1/2 is invertibte, then Tr[{∑j=1nπjSj(log Sj)^2}-A(0)^-1{∑j=1nπjH(Sj)}^2]≥0, where H(x) =- xlog x , which is a generalization of an inequality proved by K. Yanagi and others. Method These problems are settled by applying Caushy-Schwarz inequality, Jensen's inequality and some property of trace. Results The partial answers of the open problem posed by Yanagi were giv- en by these inequalities related matrix logarithm. Conclusion Some further studies on this base will been done because the results of those trace inequalities is justone case.