Half-sum of positive roots
= Half-sum of positive roots
{title2=$\rho$}
{wiki=Weyl_vector}
The Weyl vector is $\rho=\frac12\sum_{\alpha\in R^+}\alpha$. It satisfies $\langle\rho,\alpha_i^\vee\rangle=1$ for every simple root.
= Weyl vector
{c}
{synonym}