Generalization of operator type Shannon inequality and its reverse one (Advanced Topics of Information Science and Functional Analysis)
Takayuki Furuta
Abstract
We shall state the following generalization of operator type Shannoninequal- ity and its reverse one as a simple corollary of parametric extensions of Shannon inequality in Hilbert space operators.Let $\{A_{1}, A_{2}, \ldots, A_{n}\}$ andn $\{B_{1}, B_{2},\ldots, B_{n}\}n$ be two sequences of strictly positive operators on a Hilbert space H.If $E^{A_{j}=}L$ $B_{j}=I,$ thenwhere $S_{q}(A|B)=A^{\frac{1}{2}}(A^{\frac{-1}{2}}BA^{\frac{-1}{2}})^{q}(\log A^{\frac{-1}{2}}BA^{\frac{-1}{2}})A\mathrm{i}$ for $A>0$, $B>0$ and any real number $q$ and $S(A|B)=S_{0}(A|B)=A^{\frac{1}{2}}(\log A^{\frac{-1}{2}}BA^{\frac{-1}{2}})A^{\frac{1}{2}}$ which is the relative operator entropy of $A>0$ and $B>0.$Our results can be considered as parametric extensions of the following celebrated Shan- non inequality ( $[3],[5]$ and [233 $\mathrm{p},1]$ ) which is very useful and so famous in information theory.Let $\{a_{1}, a_{2}, \ldots, a_{n}\}$ and $\{b_{1}, b_{2}, \ldots, b_{n}\}$ be two probability vectors.Then $0 \geq\sum_{j=1}^{n}a_{j}\log b_{j}-\sum_{j=1}^{n}a_{j}\log a_{j}$ (see inequalities (2.4) of Corollary 2.4).