Linnemann, A.Postlethwaite, I.Anderson, B. D.O.2026-01-022026-01-020167-6911ORCID:/0000-0002-1493-4774/work/174739897https://hdl.handle.net/1885/733803060Plants with two vector inputs and two vector outputs dkbed by four rational uamfer function matrices are cwsidered. Necessary and suffident conditions are givpn for the existence of a linear time invariant finite-dimensional contmller which, when connected around one channel of the plant, leads to an internally stable closed loop system sueh that the frequency response of the remaining channel elbecomes arbitrarily small, as measured by the infinity-norm.10enAlmost disturbance decouplingdisturbance rejectiondynamic output feedbackH-infinity optimizationsystem zeros198910.1016/0167-6911(89)90054-60024641096