In this paper, we are concerned with the problem of determining the existence of multiple equilibria in economic models. We propose a general and complete approach for identifying multiplicities of equilibria in semi-algebraic economies, which may be expressed as semi-algebraic systems. The...

We review, compare and experiment with two methods for solving systems of polynomial equations. One of the methods is developed by Wu based on Ritt's concept of characteristic sets, and the other is proposed by the author in extending the idea of Seidenberg's elimination theory. We present the...