3 ms·

Thanks for pointing this out. He mentions in this one that he didn’t have time to get into Graham’s number, but I still think TREE(3) is worth mentioning.

• ThreeFx 7y ago
  Fun fact: The Kruskal Tree Theorem has been extended to undirected graphs (they form a quasi-wellordered set wrt the graph minor relationship), giving rise to an even faster growing sequence called the "Friedman's SSCG function". The theorem is interesting for other reasons though: It allows us to define graph families by forbidding certain substructures.