Traveling Salesperson Problem: Dantzig-Fulkerson-Johnson Formulation

To model the TSP, we can use multiple different formulations. They mostly differ in how they eliminate subtours, i.e., how they ensure that all locations are connected to the depot.
Dantzig, Fulkerson, and Johnson suggested several formulations based on subsets of nodes. All subsets of nodes must be connected to other parts of the route. To understand the formulation, it can help to go back to the videos on set theory in a transport context which are part of the introductory playlist ( • Introduction to OR and... )