The vibration of structures is governed by a set of second-order ordinary differential equations in which the ( f ) coefficient matrices are real. These equations often produce both complex roots and complex modes. In the established method for computing the roots, the eigenvalue problem is solved for a certain (2 f 2 ) matrix whose form is such that it contains an ( f ) submatrix of zeros as o...

A method for calculating flow polynomials based on a transfer matrix is described. It is analogous to the method used for chromatic polynomials, although there is as yet no parallel development of the theory. The new method is applied to a family of bracelets, and the limit curves for the flow roots are obtained. There is an unexplained similarity between these calculations and the correspondin...

Several matrix norms of the classical Frobenius companion matrices of a monic polynomial p(z) have been used in the literature to obtain simple lower and upper bounds on the absolute values of the roots λ of p(z). Recently, M. Fiedler has introduced a new family of companion matrices of p(z) (Lin. Alg. Appl., 372 (2003) 325-331) that has received considerable attention and it is natural to inve...

We present our public-domain software for the following tasks in sparse (or toric) elimination theory, given a well-constrained polynomial system. First, C code for computing the mixed volume of the system. Second, Maple code for defining an overconstrained system and constructing a Sylvester-type matrix of its sparse resultant. Third, C code for a Sylvester-type matrix of the sparse resultant ...

We consider the problem of writing real polynomials as determinants of symmetric linear matrix polynomials. This problem of algebraic geometry, whose roots go back to the nineteenth century, has recently received new attention from the viewpoint of convex optimization. We relate the question to sums of squares decompositions of a certain Hermite matrix. If some power of a polynomial admits a de...