利用谱分解方法研究算子Φ(Χ)=AXB的不动点与值域的关系.证明了如果算子A,B*是压缩控制算子且Φ(S)=S,则对任意的算子X∈B(H)都有‖AXB-X+S‖≥‖S‖.
This paper studies the relationship between fixed points and the range of operator Φ(Χ)=AXB by using of the spectral decomposition,and proves that ‖AXB-X+S‖≥‖S‖ for any X∈B(H) if A,B* are dominant contractions and Φ(S)=S.