Polynomial methods for the structured singular value with real parameters

The SSV (structured singular value) problem with real parameteric uncertainty only is considered. Using techniques from algebraic geometry, two algorithms that in principle can yield the precise value of the SSV at a fixed frequency are proposed. Their ability to do so depends upon their ability to find all common roots to a system of polynomial equations. The first algorithm is applicable to problems with two real parameters, each of multiplicity two. The second algorithm is applicable to problems with n distinct real parameters. These algorithms have proven useful in applications to aerospace control law analysis