If G is a graph that minimally does not embed in a nonorientable surface, then each edge of G is in a subdivision of either K3.3 or K5. However, there is an example of a graph that minimally does not embed in the torus and some edge is in no subdivision of either K3.3 or K5.
Edges and Kuratowski Subgraphs of Non-Planar Graphs
✍ Scribed by Jozef Širáň
- Publisher
- John Wiley and Sons
- Year
- 1983
- Tongue
- English
- Weight
- 225 KB
- Volume
- 113
- Category
- Article
- ISSN
- 0025-584X
No coin nor oath required. For personal study only.
✦ Synopsis
It is proved that any edge of a Pconnected non-planar graph G of order a t least 6 lies in a subdivision of K3,3 in G. For any 3-connected non-planar graph G of order a t least 6 we show that G contains at most four edges which belong to no subdivisions of K3,3 in G.
📜 SIMILAR VOLUMES
## Abstract A graph __H__ is light in a given class of graphs if there is a constant __w__ such that every graph of the class which has a subgraph isomorphic to __H__ also has a subgraph isomorphic to __H__ whose sum of degrees in __G__ is ≤ __w__. Let $\cal G$ be the class of simple planar graphs
We present a new short combinatorial proof of the sufficiency part of the well-known Kuratowski's graph planarity criterion. The main steps are to prove that for a minor minimal non-planar graph G and any edge xy: (1) G-x-y does not contain θ-subgraph; (2) G-x-y is homeomorphic to the circle; (3)
## Abstract Let ${\cal C}$ be a family of __n__ compact connected sets in the plane, whose intersection graph $G({\cal C})$ has no complete bipartite subgraph with __k__ vertices in each of its classes. Then $G({\cal C})$ has at most __n__ times a polylogarithmic number of edges, where the exponent