English

On Hamiltonian cycles in balanced $k$-partite graphs

Combinatorics 2020-05-28 v2

Abstract

For all integers kk with k2k\geq 2, if GG is a balanced kk-partite graph on n3n\geq 3 vertices with minimum degree at least n2+n+22k+12nk={n2+n+2k+1nk:k odd n2+n+2k+2nk:k even , \left\lceil\frac{n}{2}\right\rceil+\left\lfloor\frac{n+2}{2\lceil\frac{k+1}{2}\rceil}\right\rfloor-\frac{n}{k}=\begin{cases} \lceil\frac{n}{2}\rceil+\lfloor\frac{n+2}{k+1}\rfloor-\frac{n}{k} & : k \text{ odd }\\ \frac{n}{2}+\lfloor\frac{n+2}{k+2}\rfloor-\frac{n}{k} & : k \text{ even } \end{cases}, then GG has a Hamiltonian cycle unless k=2k=2 and 4 divides nn, or k=n2k=\frac{n}{2} and 4 divides nn. In the case where k=2k=2 and 4 divides nn, or k=n2k=\frac{n}{2} and 4 divides nn, we can characterize the graphs which do not have a Hamiltonian cycle and see that n2+n+22k+12nk+1\left\lceil\frac{n}{2}\right\rceil+\left\lfloor\frac{n+2}{2\lceil\frac{k+1}{2}\rceil}\right\rfloor-\frac{n}{k}+1 suffices. This result is tight for all k2k\geq 2 and n3n\geq 3 divisible by kk.

Keywords

Cite

@article{arxiv.1907.02004,
  title  = {On Hamiltonian cycles in balanced $k$-partite graphs},
  author = {Louis DeBiasio and Nicholas Spanier},
  journal= {arXiv preprint arXiv:1907.02004},
  year   = {2020}
}

Comments

14 pages, 2 figures. Minor updates

R2 v1 2026-06-23T10:11:25.447Z