Invertibility of 2×2 Upper Triangular Operator Matrices
JI Ri-g · Journal of Inner Mongolia University · 2013
Using null space and approximate null space,the sufficient and necessary conditions for 2×2upper triangular bounded operator matrices related to injective,bounded from below,surjective and invertible are studied.As an application,an equivalent condition for the invertibility of a class of upper triangular bounded Hamiltonian operators are given.Moreover,a concrete example of upper triangular bounded Hamiltonian operator is illustrated to explain the effectiveness of the criterion.