English

Geometric constructibility of polygons lying on a circular arc

Algebraic Geometry 2017-10-25 v1 Metric Geometry

Abstract

For a positive integer nn, an nn-sided polygon lying on a circular arc or, shortly, an nn-fan is a sequence of n+1n+1 points on a circle going counterclockwise such that the "total rotation" δ\delta from the first point to the last one is at most 2π2\pi. We prove that for n3n\geq 3, the nn-fan cannot be constructed with straightedge and compass in general from its central angle δ\delta and its central distances, which are the distances of the edges from the center of the circle. Also, we prove that for each fixed δ\delta in the interval (0,2π](0, 2\pi] and for every n5n\geq 5, there exists a concrete nn-fan with central angle δ\delta that is not constructible from its central distances and δ\delta. The present paper generalizes some earlier results published by the second author and \'A. Kunos on the particular cases δ=2π\delta=2\pi and δ=π\delta=\pi.

Cite

@article{arxiv.1710.08859,
  title  = {Geometric constructibility of polygons lying on a circular arc},
  author = {Delbrin Ahmed and Gábor Czédli and Eszter K. Horváth},
  journal= {arXiv preprint arXiv:1710.08859},
  year   = {2017}
}

Comments

12 pages, 1 figure

R2 v1 2026-06-22T22:24:19.122Z