论文部分内容阅读
If a 3-tuple (A:H1→H1,B:H2→H1,C:H2→H2）of operators on Hibert spaces is given,we proved that the operator ～↑A:=(↑A ↓B^*↑B ↓C) on H=H1+H2 is ≥0 is and only if A≥0,R(B)∪→R（A^1/2) and C≥B^* A^+b,where A^+ is the generalized inverse of A.In general,A^+ is a cl