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arXiv · 1810.11235

Rational Quartic Spectrahedra

Martin Helsø·Kristian Ranestad
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Abstract

Rational quartic spectrahedra in 3-space are semialgebraic convex subsets in $\mathbb{R}^3$ of semidefinite, real symmetric $(4 \times 4)$-matrices, whose boundary admits a rational parameterization. The Zariski closure in $\mathbb{C}\mathbb{P}^3$ of the boundary of a rational spectrahedron is a rational complex symmetroid. We give necessary conditions on the configurations of singularities of the corresponding real symmetroids in $\mathbb{R}\mathbb{P}^3$ of rational quartic spectrahedra. We provide an almost exhaustive list of examples realizing the configurations, and conjecture that the missing example does not occur.

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Martin Helsø, Kristian Ranestad. 2018-10-26. Rational Quartic Spectrahedra. https://arxiv.org/abs/1810.11235

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