Aperiodicity conditions for polynomials with uncertain coefficient parameters

Aperiodicity of interval polynomials is studied. Aperiodicity is normally defined as a property such that all the roots are simple and negative real, while interval polynomials are referred to as polynomials with coefficients lying within specified closed intervals on the real axis. Several conditions for aperiodicity, including an exact one, are derived. Comments on them are given in contrast to the work by Soh and Berger, who also considered the problem with a modified definition of aperiodicity.