Tractable General Equilibrium

Fuente: arXiv
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Autores principales: Goktas, Denizalp, Greenwald, Amy
Formato: Preprint
Publicado: 2025
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author Goktas, Denizalp
Greenwald, Amy
author_facet Goktas, Denizalp
Greenwald, Amy
contents We study Walrasian economies (or general equilibrium models) and their solution concept, the Walrasian equilibrium. A key challenge in this domain is identifying price-adjustment processes that converge to equilibrium. One such process, tâtonnement, is an auction-like algorithm first proposed in 1874 by Léon Walras. While continuous-time variants of tâtonnement are known to converge to equilibrium in economies satisfying the Weak Axiom of Revealed Preferences (WARP), the process fails to converge in a pathological Walrasian economy known as the Scarf economy. To address these issues, we analyze Walrasian economies using variational inequalities (VIs), an optimization framework. We introduce the class of mirror extragradient algorithms, which, under suitable Lipschitz-continuity-like assumptions, converge to a solution of any VI satisfying the Minty condition in polynomial time. We show that the set of Walrasian equilibria of any balanced economy-which includes among others Arrow-Debreu economies-corresponds to the solution set of an associated VI that satisfies the Minty condition but is generally discontinuous. Applying the mirror extragradient algorithm to this VI we obtain a class of tâtonnement-like processes, which we call the mirror extratâtonnement process. While our VI formulation is generally discontinuous, it is Lipschitz-continuous in variationally stable Walrasian economies with bounded elasticity-including those satisfying WARP and the Scarf economy-thus establishing the polynomial-time convergence of mirror extratâtonnement in these economies. We validate our approach through experiments on large Arrow-Debreu economies with Cobb-Douglas, Leontief, and CES consumers, as well as the Scarf economy, demonstrating fast convergence in all cases without failure.
format Preprint
id arxiv_https___arxiv_org_abs_2502_11449
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Tractable General Equilibrium
Goktas, Denizalp
Greenwald, Amy
Computer Science and Game Theory
Computational Engineering, Finance, and Science
Theoretical Economics
We study Walrasian economies (or general equilibrium models) and their solution concept, the Walrasian equilibrium. A key challenge in this domain is identifying price-adjustment processes that converge to equilibrium. One such process, tâtonnement, is an auction-like algorithm first proposed in 1874 by Léon Walras. While continuous-time variants of tâtonnement are known to converge to equilibrium in economies satisfying the Weak Axiom of Revealed Preferences (WARP), the process fails to converge in a pathological Walrasian economy known as the Scarf economy. To address these issues, we analyze Walrasian economies using variational inequalities (VIs), an optimization framework. We introduce the class of mirror extragradient algorithms, which, under suitable Lipschitz-continuity-like assumptions, converge to a solution of any VI satisfying the Minty condition in polynomial time. We show that the set of Walrasian equilibria of any balanced economy-which includes among others Arrow-Debreu economies-corresponds to the solution set of an associated VI that satisfies the Minty condition but is generally discontinuous. Applying the mirror extragradient algorithm to this VI we obtain a class of tâtonnement-like processes, which we call the mirror extratâtonnement process. While our VI formulation is generally discontinuous, it is Lipschitz-continuous in variationally stable Walrasian economies with bounded elasticity-including those satisfying WARP and the Scarf economy-thus establishing the polynomial-time convergence of mirror extratâtonnement in these economies. We validate our approach through experiments on large Arrow-Debreu economies with Cobb-Douglas, Leontief, and CES consumers, as well as the Scarf economy, demonstrating fast convergence in all cases without failure.
title Tractable General Equilibrium
topic Computer Science and Game Theory
Computational Engineering, Finance, and Science
Theoretical Economics
url https://arxiv.org/abs/2502.11449