arXiv subjects

Frank Göring

Publications and source records attributed to Frank Göring.

3 recordsLinked to original sources

arXiv2024

Properties of uniformly $3$-connected graphs

A graph on at least ${k+1}$ vertices is uniformly $k$-connected if each pair of its vertices is connected by $k$ and not more than $k$ independent paths. We reinvestigate a recent constructive characterization of uniformly $3$-connected graphs and obtain a more detailed result that relates the number of vertices to the operations involved in constructing a respective uniformly $3$-connected graph. Furthermore, we investigate how crossing numbers and treewidths behave under the mentioned constructions. We demonstrate how these results can be utilized to study the structure and properties of uniformly $3$-connected graphs with minimum number of vertices of minimum degree.

math.CO↗

arXiv2021

The Edge-transitive Polytopes that are not Vertex-transitive

In 3-dimensional Euclidean space there exist two exceptional polyhedra, the rhombic dodecahedron and the rhombic triacontahedron, the only known polytopes (besides polygons) that are edge-transitive without being vertex-transitive. We show that these polyhedra do not have higher-dimensional analogues, that is, that in dimension $d\ge 4$, edge-transitivity of convex polytopes implies vertex-transitivity. More generally, we give a classification of all convex polytopes which at the same time have all edges of the same length, an edge in-sphere and a bipartite edge-graph. We show that any such polytope in dimension $d\ge 4$ is vertex-transitive.

math.MG↗

arXiv2021

Uniformly connected graphs

In this article we investigate the structure of uniformly $k$-connected and uniformly $k$-edge-connected graphs. Whereas both types have previously been studied independent of each other, we analyze relations between these two classes. We prove that any uniformly $k$-connected graph is also uniformly $k$-edge-connected for $k\le 3$ and demonstrate that this is not the case for $k>3$. Furthermore, uniformly $k$-connected and uniformly $k$-edge-connected graphs are well understood for $k\le 2$ and it is known how to construct uniformly $3$-edge-connected graphs. We contribute here a constructive characterization of uniformly $3$-connected graphs that is inspired by Tuttes Wheel Theorem. Eventually, these results help us to prove a tight bound on the number of vertices of minimum degree in uniformly $3$-connected graphs.

math.CO↗