Equation 19.5.3366140D1891EC

\begin{equation} \left\{ y\in \mathbb {R}^{n-1}: (0,y)\in \Delta _{Y_{\bullet }}(\beta )\right\} =\Delta _{Y_1\supseteq \cdots \supseteq Y_ n}(\beta |_{Y_1}). \end{equation}