A Simple Extension of Dirac's Theorem on Hamiltonicity
نویسندگان
چکیده
The classical Dirac theorem asserts that every graph G on n vertices with minimum degree δ(G) ≥ dn/2e is Hamiltonian. The lower bound of dn/2e on the minimum degree of a graph is tight. In this paper, we extend the classical Dirac theorem to the case where δ(G) ≥ bn/2c by identifying the only non-Hamiltonian graph families in this case. We first present a short and simple proof. We then provide an alternative proof that is constructive and self-contained. Consequently, we provide a polynomial-time algorithm that constructs a Hamiltonian cycle, if exists, of a graph G with δ(G) ≥ bn/2c, or determines that the graph is non-Hamiltonian. Finally, we present a self-contained proof for our algorithm which provides insight into the structure of Hamiltonian cycles when δ(G) ≥ bn/2c and is promising for extending the results of this paper to the cases with smaller degree bounds.
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عنوان ژورنال:
- CoRR
دوره abs/1606.03687 شماره
صفحات -
تاریخ انتشار 2016