Periodic Inscription of Isosceles Trapezoids
Ali Naseri Sadr
TL;DR
The work addresses a periodic peg-type problem by inscribing isosceles trapezoids into a pair of disjoint periodic plane curves. It reformulates balanced inscriptions as a Lagrangian intersection problem in a Weinstein-type symplectic manifold and proves nontrivial Lagrangian Floer homology for the associated noncompact Lagrangian cylinders, guaranteeing intersections and hence balanced inscriptions. The continuous case follows from a smooth approximation via a convergence argument, yielding at least two distinct balanced inscriptions for generic smooth pairs; a rectangle corollary arises from specializing the trapezoid parameters. The results generalize square and rectangle inscriptions for periodic curves and connect discrete geometric configurations with symplectic topology methods, highlighting a novel variant of the Toeplitz square peg problem.
Abstract
We prove that a pair of continuous disjoint periodic curves in $\mathbb{C}$ inscribes an isosceles trapezoid with any similarity type. The case of smooth curves can be identified with a Lagrangian intersection problem for a pair of Lagrangian cylinders in $\mathbb{R}\times S^1\times\mathbb{C}$, and the continuous case follows from the smooth one by a standard convergence argument.
