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arXiv · 1108.2992

The Algebraic Boundary of SO(2)-Orbitopes

Rainer Sinn
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Abstract

Let $X\subset\A^{2r}$ be a real curve embedded into an even-dimensional affine space. In the main result of this paper, we characterise when the r-th secant variety to $X$ is an irreducible component of the algebraic boundary of the convex hull of the real points $X(\R)$ of $X$. This fact is then applied to 4-dimensional SO(2)-orbitopes and to the so called Barvinok-Novik orbitopes to study when they are basic closed as semi-algebraic sets. In the case of 4-dimensional SO(2)-orbitopes, we find all irreducible components of their algebraic boundary.

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Rainer Sinn. 2011-08-15. The Algebraic Boundary of SO(2)-Orbitopes. https://arxiv.org/abs/1108.2992

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