Meander diagrams of knots and spatial graphs: proofs of generalized Jablan--Radović conjectures

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Main Authors: Belousov, Yury, Malyutin, Andrei
Format: Preprint
Published: 2018
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author Belousov, Yury
Malyutin, Andrei
author_facet Belousov, Yury
Malyutin, Andrei
contents We study decomposition into simple arcs (i. e., arcs without self-intersections) for diagrams of knots and spatial graphs. In this paper, it is proved in particular that if no edge of a finite spatial graph $G$ is a knotted loop, then there exists a plane diagram $D$ of $G$ such that (i) each edge of $G$ is represented by a simple arc of $D$ and (ii) each vertex of $G$ is represented by a point on the boundary of the convex hull of $D$. This generalizes the conjecture of S. Jablan and L. Radović stating that each knot has a meander diagram, i. e., a diagram composed of two simple arcs whose common endpoints lie on the boundary of the convex hull of the diagram. Also, we prove another conjecture of Jablan and Radović stating that each 2-bridge knot has a semi-meander minimal diagram, i. e., a minimal diagram composed of two simple arcs.
format Preprint
id arxiv_https___arxiv_org_abs_1803_10879
institution arXiv
publishDate 2018
record_format arxiv
spellingShingle Meander diagrams of knots and spatial graphs: proofs of generalized Jablan--Radović conjectures
Belousov, Yury
Malyutin, Andrei
Geometric Topology
57M25
We study decomposition into simple arcs (i. e., arcs without self-intersections) for diagrams of knots and spatial graphs. In this paper, it is proved in particular that if no edge of a finite spatial graph $G$ is a knotted loop, then there exists a plane diagram $D$ of $G$ such that (i) each edge of $G$ is represented by a simple arc of $D$ and (ii) each vertex of $G$ is represented by a point on the boundary of the convex hull of $D$. This generalizes the conjecture of S. Jablan and L. Radović stating that each knot has a meander diagram, i. e., a diagram composed of two simple arcs whose common endpoints lie on the boundary of the convex hull of the diagram. Also, we prove another conjecture of Jablan and Radović stating that each 2-bridge knot has a semi-meander minimal diagram, i. e., a minimal diagram composed of two simple arcs.
title Meander diagrams of knots and spatial graphs: proofs of generalized Jablan--Radović conjectures
topic Geometric Topology
57M25
url https://arxiv.org/abs/1803.10879