Popis: |
We present the first combinatorial polynomial time algorithm for computing the equilibrium of the Arrow-Debreu market model with linear utilities. Our algorithm views the allocation of money as flows and iteratively improves the balanced flow as in 11] for Fisher's model. We develop new methods to carefully deal with the flows and surpluses during price adjustments. Our algorithm performs O ( n 6 log ? ( n U ) ) maximum flow computations, where n is the number of agents and U is the maximum integer utility. The flows have to be presented as numbers of bitlength O ( n log ? ( n U ) ) to guarantee an exact solution. Previously, 22,29] have given polynomial time algorithms for this problem, which are based on solving convex programs using the ellipsoid algorithm and the interior-point method, respectively. |