On a Duality Between Kruskal and Dershowitz Theorems

The article is mainly concernedwith the Kruskal tree theorem and the following observation: there is a duality at the level of binary relations between well and noetherian orders. The first step here is to extend Kruskal theorem from orders to binary relations so that the duality applies. Then, we describe the theorem obtained by duality and show that it corresponds to a theorem by Ferreira and Zantema which subsumesDershowitz’s seminal results on recursive path orderings.