English

Symplectically convex and symplectically star-shaped curves -- a variational problem

Symplectic Geometry 2022-12-29 v3 Differential Geometry

Abstract

In this article we propose a generalization of the 2-dimensional notions of convexity resp. being star-shaped to symplectic vector spaces. We call such curves symplectically convex resp. symplectically star-shaped. After presenting some basic results we study a family of variational problems for symplectically convex and symplectically star-shaped curves which is motivated by the affine isoperimetric inequality. These variational problems can be reduced back to two dimensions. For a range of the family parameter extremal points of the variational problem are rigid: they are multiply traversed conics. For all family parameters we determine when non-trivial first and second order deformations of conics exist. In the last section we present some conjectures and questions and two galleries created with the help of a Mathematica applet by Gil Bor.

Keywords

Cite

@article{arxiv.2012.14797,
  title  = {Symplectically convex and symplectically star-shaped curves -- a variational problem},
  author = {Peter Albers and Serge Tabachnikov},
  journal= {arXiv preprint arXiv:2012.14797},
  year   = {2022}
}

Comments

23 pages, 5 figures; v3: various minor typos corrected

R2 v1 2026-06-23T21:33:38.197Z