Partitioning the projective plane to two incidence-rich parts

Fuente: arXiv
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Main Author: Nagy, Zoltán Lóránt
Format: Preprint
Published: 2024
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author Nagy, Zoltán Lóránt
author_facet Nagy, Zoltán Lóránt
contents An internal or friendly partition of a vertex set $V(G)$ of a graph $G$ is a partition to two nonempty sets $A\cup B$ such that every vertex has at least as many neighbours in its own class as in the other one. Motivated by Diwan's existence proof on internal partitions of graphs with high girth, we give constructive proofs for the existence of internal partitions in the incidence graph of projective planes and discuss its geometric properties. In addition, we determine exactly the maximum possible difference between the sizes of the neighbor set in its own class and the neighbor set of the other class, that can be attained for all vertices at the same time for the incidence graphs of desarguesian planes of square order.
format Preprint
id arxiv_https___arxiv_org_abs_2403_13734
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Partitioning the projective plane to two incidence-rich parts
Nagy, Zoltán Lóránt
Combinatorics
An internal or friendly partition of a vertex set $V(G)$ of a graph $G$ is a partition to two nonempty sets $A\cup B$ such that every vertex has at least as many neighbours in its own class as in the other one. Motivated by Diwan's existence proof on internal partitions of graphs with high girth, we give constructive proofs for the existence of internal partitions in the incidence graph of projective planes and discuss its geometric properties. In addition, we determine exactly the maximum possible difference between the sizes of the neighbor set in its own class and the neighbor set of the other class, that can be attained for all vertices at the same time for the incidence graphs of desarguesian planes of square order.
title Partitioning the projective plane to two incidence-rich parts
topic Combinatorics
url https://arxiv.org/abs/2403.13734