Before revision:  Rational expectations require time-varying and correlated support restrictions on the distribution of the structural shocks. With appropriate restrictions , a very large number of equilibria can be supported .
After revision:  Rational expectations require time-varying and correlated support restrictions on the distribution of the shocks. These restrictions are rarely explicitly acknowledged or imposed in the literature. Models whose coherency is based on support restrictions are generically incomplete, admitting a very large number of equilibria can be supported .