  The notions of basic controllability and basic control are defined using
dynamical systems theory of partial differential equations. A quadratic optimal
control of the linearized viscous Moore-Greitzer equation is presented and it
is confirmed that stall is uncontrollable in this model. A basic control is
constructed for the nonlinear viscous Moore-Greitzer equation which can control
both surge and stall. Numerical simulations of the basic control are presented.
