The Nehari problem for nonexponentially stable systems

The Nehari problem and its suboptimal extension are solved under the assumption that the system (A, B, C) has bounded controllability and observability maps, an L₂-impulse response and a transfer matrix that is bounded and holomorphic on the right half-plane. Exponential stability of the semigroup is not assumed and the Hankel operator is not compact. The new contribution is an explicit parameterization of all solutions given in terms of the system parametersA, B, C.