Determinantal representations of hyperbolic curves via polynomial   homotopy continuation
  A smooth curve in the real projective plane is hyperbolic if its ovals are maximally nested. By the Helton-Vinnikov Theorem, any such curve admits a definite symmetric determinantal representation. We use polynomial homotopy continuation to compute such representations numerically. Our method works by lifting paths from the space of hyperbolic polynomials to a branched cover in the space of pairs of symmetric matrices. 
Anton Leykin, Daniel Plaumann
math.AG math.OC