Hoàng's degree-sequence conjecture for tough graphs
Let be a simple graph. Write for its number of components, and define its toughness by
when is not complete, with otherwise. The graph is -tough if . Let be the degree sequence of an -vertex graph .
Hoàng's conjecture. Let and be integers. If is -tough and, for every , implies , then is Hamiltonian.
This conjecture is a toughness analogue of Chvátal's degree-sequence theorem. Hoàng proved it for , Hoàng and Robin proved it for , and the source states that it has been confirmed for all ; thus the conjecture is solved.
References
Primary source
Songling Shan and Arthur Tanyel, “A strengthening of a degree sequence condition for Hamiltonicity in tough graphs”, arXiv:2503.14735 (2025).
Additional references
2 papers in this index state this conjecture (2023–2025). The statement above is taken from the most recent of them; the others are arXiv:2303.03479.
Progress summary
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