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arXiv · 2504.02907

Circular Isoptics in Flatland

Alexander Thomas
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Abstract

We explore convex shapes $S$ in the Euclidean plane which have the following property: there is a circle $C$ such that the angle between the two tangents from any point of $C$ to $S$ is constant equal to $α$. A dynamical formulation allows to analyze the existence of such shapes. Interestingly, the existence of non-circular shapes depends in a non-trivial way on the angle $α$.

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Alexander Thomas. 2025-04-03. Circular Isoptics in Flatland. https://arxiv.org/abs/2504.02907

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