We present eecient and accurate algorithms to compute solutions of zero-dimensional multivariate polynomial equations in a given domain. The total number of solutions correspond to the Bezout bound for dense polynomial systems or the Bernstein bound for sparse systems. In most applications the actual number of solutions in the domain of interest is much lower than the Bezout or Bernstein bound....

First, recall how Bezout’s Theorem can be made more precise by specifying the meaning of the word “generically” used above, using elementary scheme-theoretic language ([H, II]). Fix an algebraically closed field k. There is little loss in assuming k = C (until Section 3). Since we work over an algebraically closed field, we often identify reduced algebraic sets with their k-valued points. In th...

In this paper we consider the following analog of Bezout inequality for mixed volumes: V (P1, . . . , Pr,∆ )Vn(∆) r−1 ≤ r ∏ i=1 V (Pi,∆ ) for 2 ≤ r ≤ n. We show that the above inequality is true when ∆ is an n -dimensional simplex and P1, . . . , Pr are convex bodies in R . We conjecture that if the above inequality is true for all convex bodies P1, . . . , Pr , then ∆ must be an n -dimensional...

We consider in this paper the simultaneous problem of optimal robust stabilization and optimal tracking for SISO systems in an L 1-setting using a two-parameter compensator scheme. Optimal robustness is linked to the work done by Georgiou and Smith in the L 2-setting. Optimal tracking involves the resolution of L 1-optimization problems. We consider in particular the robust control of delay sys...