stats# mean(x, rep_x) Estimate the \(\mathbb{G}\)-invariant mean of a random variable. var(x, rep_x[, center]) Estimate the symmetry-constrained variance of \(\mathbf{X}:\Omega\to\mathcal{X}\). var_mean(x, rep_x) Compute var() and mean() under symmetry constraints. cov(x, y, rep_x, rep_y) Compute the covariance between two symmetric random variables.