2019/08/29 by Krishna, K. Mahesh, Johnson, P. Sam, Mohapatra, R. N.
#42C15 #46C05 #47A05 #47L20 #FOS: Mathematics #Functional Analysis (math.FA)
paper · doi:10.48550/arxiv.1908.11059
Let \λn\n ∈ ℓ^∞(ℕ). In 1960, R. Schatten \citeSCHATTEN studied operators of the form ∑n=1∞λn (xn⊗ yn), where \xn\n, \yn\n are orthonormal sequences in a Hilbert space. In 2007, P. Balazs \citeBALAZS3 generalized this by replacing \xn\n and \yn\n by Bessel sequences. In this paper, we generalize this by studying the operators of the form ∑n=1∞λn (A^*nxn⊗ B^*nyn), where \An\n and \Bn\n are operator-valued Bessel sequences and \xn\n, \yn\n are sequences in the Hilbert space such that \‖xn‖‖yn‖\n ∈ ℓ^∞(ℕ). We next generalize the classes of Hilbert-Schmidt and trace class operators.