Dirac's theorem

Dirac's theorem may refer to:
 * Dirac's theorem on Hamiltonian cycles, the statement that an $n$-vertex graph in which each vertex has degree at least $n/2$ must have a Hamiltonian cycle
 * Dirac's theorem on chordal graphs, the characterization of chordal graphs as graphs in which all minimal separators are cliques
 * Dirac's theorem on cycles in $k$-connected graphs, the result that for every set of $k$ vertices in a $k$-vertex-connected graph there exists a cycle that passes through all the vertices in the set