REFINEMENTS OF THE NORM OF TWO ORTHOGONAL PROJECTIONS  

作　　者：Xiaohui LI Meiqi LIU Chunyuan DENG 李晓辉;刘美琪;邓春源(School of Mathematics Science,South China Normal University,Guangzhou 510631,China)

机构地区：[1]School of Mathematics Science,South China Normal University,Guangzhou 510631,China

出　　处：《Acta Mathematica Scientia》2024年第4期1229-1243,共15页数学物理学报（B辑英文版）

摘　　要：In this paper,some refinements of norm equalities and inequalities of combination of two orthogonal projections are established.We use certain norm inequalities for positive contraction operator to establish norm inequalities for combination of orthogonal projections on a Hilbert space.Furthermore,we give necessary and sufficient conditions under which the norm of the above combination of o`rthogonal projections attains its optimal value.

关 键 词：NORM orthogonal projection positive operator SPECTRAL block operator valued matrix 

分 类 号：O177[理学—数学]