THE K-RING OF E_6/Spin(10)

Let $\mathrm E_6$ denote the simply-connected compact exceptional Lie group of rank 6. The Lie group $\mathrm Spin(10)$ naturally embeds in $\mathrm E_6$, corresponding to the inclusion of the Dynkin diagrams. We determine the K-ring of the coset space ${\mathrm E}_6/\mathrm Spin(10)$. We identify the class of the tangent bundle of ${\mathrm E}_6/\mathrm Spin(10)$ in $KO({\mathrm E}_6/\mathrm Spin(10))$. As an application we show that ${\mathrm E}_6/\mathrm Spin(10)$ can be immersed in the Euclidean space $\mathbb R^{53}$.