Decouplingoflineartime-invariantsystemsbystatefeedbackandprecompensationhasbeentreatedinseveralpapers(FalbandWolovich1967,Gilbert1969,WonhamandMorse1970,SilvermanandPayne1(71).Ageneralizationofsomeresultsfortime-variablesystemswasgivenbyPorter(1969)andFreund(1971a,b).Decouplingofnon-