Editing Robertson–Seymour theorem (section)

==Finite form of the graph minor theorem==
{{harvtxt|Friedman|Robertson|Seymour|1987}} showed that the following theorem exhibits the [[Independence (mathematical logic)|independence]] phenomenon by being ''unprovable'' in various formal systems that are much stronger than [[Peano arithmetic]], yet being ''provable'' in systems much weaker than [[ZFC]]:
 
{{bi|left=1.6|'''Theorem''': For every positive integer <math>n</math>, there is an integer <math>m</math> so large that if <math>G_1,\dots, G_m</math> is a sequence of finite undirected graphs, where each <math>G_i</math> has size at most <math>n+i</math>, then <math>G_j\le G_k</math> for some <math>j\le k</math>.}}

(Here, the ''size'' of a graph is the total number of its vertices and edges, and ≤ denotes the minor ordering.)