On the solutions of deformed algebraic systems
S. Tanabe, M. N. Vrahatis
TL;DR
This study addresses how the real roots of a system of polynomial equations respond to small deformations. It develops a perturbation bound and a homotopy framework that guarantee the real root count inside a fixed compact set remains unchanged, counting multiplicities, when the perturbation parameter $t$ satisfies $t < \frac{1}{\|\varphi\|\,C(a)\,\mu^2}$. It also establishes a Bertini-Sard-type result ensuring that multiple roots can be decomposed into simple roots via an appropriate perturbation vector $H$, with explicit low-dimensional examples illustrating root-splitting and symmetry-preserving behavior. The results have practical impact for reliable root counting and topology-preserving deformation of real algebraic sets, with potential applications in computer-aided design and graphics, where intersections and perturbations of hypersurfaces are common.
Abstract
A problem concerning the shift of roots of a system of homogeneous algebraic equations is investigated. Its conservation and decomposition of a multiple root into simple roots are discussed.
