Euclidean designs obtained from Q-polynomial coherent configurations
摘要
Euclidean t-designs are the two-step generalization of spherical t-designs, and coherent configurations are the extension of association schemes. It was proved that the spherical embedding of Q-polynomial association schemes can become spherical t-designs under certain conditions. In this paper, we extend the Sidelnikov inequality to Euclidean space and present an equivalent condition of Euclidean t-designs. As the main result, we propose a necessary and sufficient condition for the spherical embedding of a Q-polynomial coherent configuration (with two fibers) to be a Euclidean t-design (on two concentric spheres) for any positive integer t. In addition, we prove