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.

Graph theory isn’t enough. The mathematical language for talking about connections, which usually depends on networks — vertices (dots) and edges (lines connecting them) — has been an invaluable way ...

The difficulty of some mathematical problems lies in not knowing how hard they are. This is the case with an important problem in computer science called "graph isomorphism testing" whereby ...