Graph theory is well developed in other fields, including geography (transportation networks, routing applications, siting problems) and computer science (circuitry and network optimization).

Thomas E. Dilts, Peter J. Weisberg, Philip Leitner, Marjorie D. Matocq, Richard D. Inman, Kenneth E. Nussear, Todd C. Esque, Multiscale connectivity and graph theory ...

The main challenge here lies in devising a mathematically acceptable proof of this impossibility, which is where the foundations for what we today know as graph theory.