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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.

Periodic Inscription of Isosceles Trapezoids

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 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 , and the continuous case follows from the smooth one by a standard convergence argument.

Paper Structure

This paper contains 3 sections, 8 theorems, 16 equations, 1 figure.

Key Result

Theorem 1.2

Suppose $\gamma_1$ and $\gamma_2$ are two continuous disjoint periodic embeddings of the real line into the plane, and suppose $Q$ is an isosceles trapezoid. Then $(\gamma_1$, $\gamma_2)$ admits a balanced inscription of $Q$. Furthermore, there is a generic subset of smooth disjoint periodic pairs s

Figures (1)

  • Figure 1: An annotated isosceles trapezoid $Q$.

Theorems & Definitions (19)

  • Definition 1.1
  • Theorem 1.2
  • Corollary 1.3
  • Conjecture 1.4
  • Remark
  • Lemma 2.1
  • Corollary 2.2
  • proof
  • Lemma 2.3
  • proof
  • ...and 9 more