Stabilization of a class of plants with possible loss of outputs or actuator failures

The loss of one or more outputs of a plant is reflected by one or more rows of zeros in the plant's transfer function. In this note, the simultaneous stabilization of a plant and the same plant with loss of outputs is considered. Necessary and sufficient conditions for simultaneous stabilization of a class of plants are given as well as a simple test to determine the existence of such a controller. Actuator failure is also considered at the end as a dual problem.