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arXiv · 2610.22772

Semialgebraic ${C^m}$ solutions to a univariate system of linear inequalities with Nash forcing

Fushuai Jiang·Garving K. Luli
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Abstract

Let $(A_{ij}(x))_{1 \leq i \leq N, 1 \leq j \leq M}$ be a matrix of univariate semialgebraic functions. We study the solvability of the system of linear inequalities \begin{equation*} \sum_{j=1}^M A_{ij}(x)F_j(x)\leq f_i(x) \ \ \text{ for } i = 1, \ldots, N, \end{equation*} where we assume each forcing $f_i$ is a Nash function. We show that the $C^m$ solvability of the system can be characterized by finitely many linear ordinary differential inequalities in $f$ with semialgebraic coefficients depending only on $(A_{ij})$. When the system is solvable, the solution may be chosen semialgebraic, and the proof gives a constructive procedure in the semialgebraic sense. We also study the semimodule structure of admissible forcings, establishing finite generation and lack thereof in various settings.

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Fushuai Jiang, Garving K. Luli. 2026-10-16. Semialgebraic ${C^m}$ solutions to a univariate system of linear inequalities with Nash forcing. https://arxiv.org/abs/2610.22772

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