Computing critical points for invariant algebraic systems

JC Faugère, G Labahn, MS El Din, É Schost… - Journal of Symbolic …, 2023 - Elsevier
Let K be a field and (f 1,…, fs, ϕ) be multivariate polynomials in K [x 1,…, xn](with s< n) each
invariant under the action of S n, the group of permutations of {1,…, n}. We consider the …

Vandermonde varieties, mirrored spaces, and the cohomology of symmetric semi-algebraic sets

S Basu, C Riener - Foundations of Computational Mathematics, 2022 - Springer
Let R be a real closed field. We prove that for each fixed ℓ, d≥ 0, there exists an algorithm
that takes as input a quantifier-free first-order formula Φ with atoms P= 0, P> 0, P< 0 with P∈ …

[HTML][HTML] Symmetric semi-algebraic sets and non-negativity of symmetric polynomials

C Riener - Journal of Pure and Applied Algebra, 2016 - Elsevier
The question of how to certify the non-negativity of a polynomial function lies at the heart of
Real Algebra and has important applications to optimization. Building on work by Choi, Lam …

Real root finding for equivariant semi-algebraic systems

C Riener, M Safey el Din - Proceedings of the 2018 ACM International …, 2018 - dl.acm.org
Let R be a real closed field. We consider basic semi-algebraic sets defined by n-variate
equations/inequalities of s symmetric polynomials and an equivariant family of polynomials …

Faster real root decision algorithm for symmetric polynomials

G Labahn, C Riener, M Safey El Din, É Schost… - Proceedings of the 2023 …, 2023 - dl.acm.org
In this paper, we consider the problem of deciding the existence of real solutions to a system
of polynomial equations having real coefficients, and which are invariant under the action of …

How to flatten a soccer ball

K Kubjas, PA Parrilo, B Sturmfels - … : Dedicated to Winfried Bruns on the …, 2017 - Springer
This is an experimental case study in real algebraic geometry, aimed at computing the
image of a semialgebraic subset of 3-space under a polynomial map into the plane. For …

On the isotypic decomposition of cohomology modules of symmetric semi-algebraic sets: polynomial bounds on multiplicities

S Basu, C Riener - International Mathematics Research Notices, 2020 - academic.oup.com
We consider symmetric (under the action of products of finite symmetric groups) real
algebraic varieties and semi-algebraic sets, as well as symmetric complex varieties in affine …

Efficient algorithms for computing the euler-poincaré characteristic of symmetric semi-algebraic sets

S Basu, C Riener - … on Ordered Algebraic Structures and Related …, 2017 - books.google.com
Let R be a real closed field and D⊂ R an ordered domain. We consider the algorithmic
problem of computing the generalized Euler-Poincaré characteristic of real algebraic as well …

Multiple points of a simplicial map and image-computing spectral sequences

JL Cisneros-Molina, D Mond - arXiv preprint arXiv:1911.11095, 2019 - arxiv.org
The Image-Computing Spectral Sequence computes the homology of the image of a finite
map from the alternating homology of the multiple point spaces of the map. A related …

[HTML][HTML] Deciding positivity of multisymmetric polynomials

P Görlach, C Riener, T Weißer - Journal of Symbolic Computation, 2016 - Elsevier
The question how to certify non-negativity of a polynomial function lies at the heart of Real
Algebra and also has important applications to Optimization. In this article we investigate the …