%0 Journal Article
%T On the diameter of the commuting graph of the full matrix ring over the real numbers
%A Jose Maria Grau
%A Antonio Oller-Marcen
%A Carmen Tasis
%J Mathematics
%D 2014
%I arXiv
%X In a recent paper C. Miguel proved that the diameter of the commuting graph of the matrix ring $\mathrm{M}_n(\mathbb{R})$ is equal to $4$ either if $n=3$ or $n>4$. But the case $n=4$ remained open, since the diameter could be $4$ or $5$. In this work we close the problem showing that also in this case the diameter is equal to $4$.
%U http://arxiv.org/abs/1412.0541v1