Koplienko-Neidhardt trace formula for pairs of contraction operators and pairs of maximal dissipative operators

摘要

We present a generalization of Koplienko-Neidhardt trace formula for pairs of Hilbert space operators (T, V) with T contractive and V unitary such that T - V is a Hilbert-Schmidt operator. We extend the result to pairs of contractions and then, via Cayley transform, to pairs of maximal dissipative operators.