build_Ej                Build E_j tensor structure
calculate_u_statistics_pure_r_six
                        Compute U-statistics HOIF-type from Order 2 to
                        6 in pure R code.
compute_basis_matrix    Compute basis projection matrices
compute_gram_inverse    Compute inverse of weighted Gram matrix
compute_hoif_estimators
                        Compute HOIF Estimators for ATE
compute_residuals       Compute residuals for both treatment groups
hoif_ate                Main function: HOIF estimators for ATE with
                        optional sample splitting
plot.hoif_ate           Plot convergence of ATE estimates
print.hoif_ate          Print method for hoif_ate objects
transform_covariates    HOIF Estimators for Average Treatment Effect
