On winding numbers of almost embeddings of $K_4$ in the plane

Fuente: arXiv
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Main Authors: Alkin, Emil, Miroshnikov, Alexander
Format: Preprint
Published: 2025
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_version_ 1866918010511425536
author Alkin, Emil
Miroshnikov, Alexander
author_facet Alkin, Emil
Miroshnikov, Alexander
contents Let $K_4$ be the complete graph on four vertices. Let $f$ be a continuous map of $K_4$ to the plane such that $f$-images of non-adjacent edges are disjoint. For any vertex $v \in K_4$ take the winding number of the $f$-image of the cycle $K_4 - v$ around $f(v)$. It is known that the sum of these four integers is odd. We construct examples showing that this is the only relation between these four numbers.
format Preprint
id arxiv_https___arxiv_org_abs_2501_15642
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle On winding numbers of almost embeddings of $K_4$ in the plane
Alkin, Emil
Miroshnikov, Alexander
Geometric Topology
Computational Geometry
Combinatorics
57M15, 55M25, 05C10
Let $K_4$ be the complete graph on four vertices. Let $f$ be a continuous map of $K_4$ to the plane such that $f$-images of non-adjacent edges are disjoint. For any vertex $v \in K_4$ take the winding number of the $f$-image of the cycle $K_4 - v$ around $f(v)$. It is known that the sum of these four integers is odd. We construct examples showing that this is the only relation between these four numbers.
title On winding numbers of almost embeddings of $K_4$ in the plane
topic Geometric Topology
Computational Geometry
Combinatorics
57M15, 55M25, 05C10
url https://arxiv.org/abs/2501.15642