We say that two graphs G and H with the same vertex set commute if their adjacency matrices commute. In this article, we show that for any natural number r, the complete multigraphK n is decomposable into commuting perfect matchings if and only if n is a 2-power. Also, it is shown that the complete graph Kn is decomposable into commuting Hamilton cycles if and only if n is a prime number. © 200...

Let G be a finite non-abelian group and Z(G) its center. We associate commuting graph $$\Gamma (G)$$ to G, whose vertex set is $$G\setminus Z(G)$$ two distinct vertices are adjacent if they commute. In this paper we prove that the of all groups has maximum degree bounded above by fixed $$k \in {\mathbb {N}}$$ finite. Also, characterize for which associated graphs have at most 4.

This paper considers commuting graphs over the semidihedral group SD8n. We compute their eigenvalues and obtain that these are not hyperenergetic for odd n≥15 or even n≥2. further Laplacian spectrum, energy number of spanning trees also discuss vertex connectivity, planarity, minimum disconnecting sets prove Hamiltonian.