Using Integer Programming to Search for Counterexamples: A Case Study

Autor: Giuseppe Lancia, Franca Rinaldi, Eleonora Pippia
Rok vydání: 2020
Předmět:
Zdroj: Mathematical Optimization Theory and Operations Research ISBN: 9783030499877
MOTOR
DOI: 10.1007/978-3-030-49988-4_5
Popis: It is known that there exist 4-regular, 1-tough graphs which are non-hamiltonian. The smallest such graph known has \(n=18\) nodes and was found by Bauer et al., who conjectured that all 4-regular, 1-tough graphs with \(n\le 17\) are hamiltonian. They in fact proved that this is true for \(n\le 15\), but left open the possibility of non-hamiltonian graphs of 16 or 17 nodes. By using ILP for modeling a counterexample, and then finding out that the model has no solutions, we give an algorithmic proof that their conjecture was indeed correct.
Databáze: OpenAIRE