inexplicit equations in PRED

Dear NMusers, Most of the models are pre-defined (ADVANx), expressed as a system of differential equations or provided in the form of an explicit mathematical equation (PRED). Is it possible to deal with nonlinear inexplicit equations like y = f(x,y) where both differential equations and explicit solution equation are not known or not obvious. Concretely, using PRED, one would find F on the both sides: F = f(X) + g(F) Y = F+EPS(1) Many thanks in advance Best regards, Robert ___________________________________________ Robert M. Kalicki, MD Postdoctoral Fellow Department of Nephrology and Hypertension Inselspital University of Bern Switzerland Address: Klinik und Poliklinik für Nephrologie und Hypertonie KiKl G6 Freiburgstrasse 15 CH-3010 Inselspital Bern Tel +41(0)31 632 96 63 Fax +41(0)31 632 14 58