The twisted cube TQn is a variant of the hypercube Qn. It has been shown by Chang, Wang and Hsu [Topological properties of twisted cube. Information Science, 113, 147-167 （1999）] that TQn contains a cycle of every length from 4 to 2^n. In this paper, we improve this result by showing that every edge of TQn lies on a cycle of every length from 4 to 2^n inclusive. We also show that the twisted cube are Hamiltonian connected.
The bubble-sort graph Bn is a bipartite graph. Kikuchi and Araki [Edge-bipancyclicity and edge-fault-tolerant bipancyclicity of bubble-sort graphs. Information Processing Letters, 100, 52- 59 （2006）] have proved that Bn is edge-bipancyclic for n ≤ 5 and Bn - F is bipancyclic when n ≥ 4 and IFI≤ n - 3. In this paper, we improve this result by showing that for any edge set F of Bn with IFI ≤ n - 3, every edge of Bn - F lies on a cycle of every even length from 6 to n! for n≤ 5 and every edge of Bn - F lies on a cycle of every even length from 8 to n! for n = 4.
