General Clark model for finite-rank perturbations
General Clark model for finite-rank perturbations is a scholarly work, published in 2019 in ''Analysis & PDE''. The main subjects of the publication include self-adjoint operator, shift operator, mathematical analysis, pure mathematics, rank, unitary representation, unitary state, spectral theory, numerical linear algebra, operon, unitary operator, contraction, unit circle, combinatorics, mathematics, unit vector, and complex analysis. The authors make no assumptions on the spectral type of the unitary operator math ; an absolutely continuous spectrum may be present.\n¶ We first find a universal representation of the adjoint Clark operator in the coordinate-free Nikolski–Vasyunin functional model; the word “universal” means that it is valid in any transcription of the model.