Before revision:  We show that a subclass of synthesis functions under Bayesian predictive synthesis , which we categorize as non-linear synthesis,  entails an extra term  that "corrects" the bias from misspecification and dependence in the predictive error process , effectively improving forecasts.
After revision:  We identify a class of forecast combination methods , which we categorize as non-linear synthesis, entails an extra term that "corrects" the bias from misspecification and dependence in the predictive error process , effectively improving forecasts.