IDENTIFYING RESTRICTIONS OF LINEAR-EQUATIONS WITH APPLICATIONS TO SIMULTANEOUS-EQUATIONS AND COINTEGRATION

The identification problem for simultaneous equations is solved by the well-known rank condition which gives a necessary and sufficient cond ition for the parameters to be uniquely or statistically identified by linear restrictions. This paper formulates and solves another problem : Given a set of linear restrictions, which conditions should they sat isfy for most parameter values to be identified? The main result of th e paper is a simple algebraic condition on a set of linear restriction s that guarantees that most parameters satisfying the restrictions are uniquely identified.