Topological Minors
A graph H is called a topological minor of a graph G if a subdivision of H is isomorphic to a subgraph of G. It is easy to see that every topological minor is also a minor. The converse however is not true in general, but holds for graph with maximum degree not greater than three.
The topological minor relation is not a well-quasi-ordering on the set of finite graphs and hence the result of Robertson and Seymour does not apply to topological minors. However it is straightforward to construct finite forbidden topological minor characterizations from finite forbidden minor characterizations by replacing every branch set with k outgoing edges by every tree on k leaves that has down degree at least two.
Read more about this topic: Graph Minor