This paper proposes a new nonparametric estimator for general regression functions with multiple regressors. The method used here is motivated by a remarkable result derived by Kolmogorov (1957) and later tightened by Lorentz (1966). In short, they show that any continuous function of multiple...

In this paper, we consider expectations of the form E[log(y)|x] = a'log(x) as a good starting point for a more general analysis. We show why this naturally leads to the following flexible functional form E[y|x]= f(h(x)), where all functions are estimated by cubic splines. One of the main goals...