CFI upper triangular operator matrices
Jiong Dong, Xiaohong Cao · Linear and Multilinear Algebra · 2022
Let H and K be complex infinite dimensional separable Hilbert spaces. For given operators A∈B(H) and B∈B(K), we provide necessary and sufficient conditions which make a 2×2 upper triangular operator matrix MC=(AC0B) a CFI operator for some (or every) C∈B(K,H).