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Bibliographic Details
Main Authors: Dunshee, Blake, Ellingham, M. N.
Format: Preprint
Published: 2024
Subjects:
Online Access:https://arxiv.org/abs/2501.00596
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author Dunshee, Blake
Ellingham, M. N.
author_facet Dunshee, Blake
Ellingham, M. N.
contents We consider seven fundamental properties of cellular embeddings of graphs in compact surfaces, and show that each property can be associated with a point of the Fano plane $F$, in such a way that allowable combinations of properties correspond to projective subspaces of $F$. This Fano framework allows us to deduce a number of implications involving the seven properties, providing new results and unifying existing ones. For each property, we provide a correspondence between embeddings with that property and an associated structure for $4$-regular graphs, using the medial graph of the graph embedding. We apply this to characterize when a graph embedding has a twisted dual with one of the properties. For each allowable combination of properties, we show that a graph embedding with these properties exists. We investigate connections between the seven properties and three weaker `Eulerian' properties. Our proofs involve parity conditions on closed walks in an extended version of the `gem' (graph-encoded map) representation of a graph embedding.
format Preprint
id arxiv_https___arxiv_org_abs_2501_00596
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle A Fano framework for embeddings of graphs in surfaces
Dunshee, Blake
Ellingham, M. N.
Combinatorics
05C10
We consider seven fundamental properties of cellular embeddings of graphs in compact surfaces, and show that each property can be associated with a point of the Fano plane $F$, in such a way that allowable combinations of properties correspond to projective subspaces of $F$. This Fano framework allows us to deduce a number of implications involving the seven properties, providing new results and unifying existing ones. For each property, we provide a correspondence between embeddings with that property and an associated structure for $4$-regular graphs, using the medial graph of the graph embedding. We apply this to characterize when a graph embedding has a twisted dual with one of the properties. For each allowable combination of properties, we show that a graph embedding with these properties exists. We investigate connections between the seven properties and three weaker `Eulerian' properties. Our proofs involve parity conditions on closed walks in an extended version of the `gem' (graph-encoded map) representation of a graph embedding.
title A Fano framework for embeddings of graphs in surfaces
topic Combinatorics
05C10
url https://arxiv.org/abs/2501.00596