The Minimal Polynomial of a Riemannian C_0-Space
Tillmann Jentsch
TL;DR
This work introduces a curvature-based invariant for Riemannian $\mathfrak{C}_0$-spaces by constructing a pointwise minimal polynomial $P_{\min}(M,g,p)$ from the symmetrized covariant derivatives of the curvature. On homogeneous spaces, these pointwise polynomials glue to a global polynomial with coefficients that are Killing tensors invariant under the full isometry group, and the polynomial degree provides an upper bound for the Singer invariant. The paper develops an algebraic framework ensuring existence and uniqueness of such polynomials under a kernel-ideal condition, and proves that for $\mathfrak{C}_0$-spaces the coefficients become global invariant tensors on suitable regions; it also provides explicit examples and discusses the implications for geometric structure and symmetry. The results connect deep algebraic properties of curvature jets with tangible geometric objects, offering both concrete invariants and a path to understanding symmetry in Riemannian geometry. Overall, the minimal polynomial serves as a bridge between curvature derivatives, Killing tensors, and invariants of symmetry in C0-spaces, with potential to illuminate homogeneity and stability phenomena in geometric analysis.
Abstract
We construct, at every point of a Riemannian C_0-space, a polynomial in one variable whose coefficients are polynomial functions on the tangent space. For a homogeneous Riemannian C_0-space (for instance, a G.O. space) these pointwise-defined polynomials glue to a global polynomial whose coefficients are Killing tensors invariant under the full isometry group. Moreover, the degree of this polynomial provides an upper bound for the Singer invariant of the space.
