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We study a decentralized trading model as in [7], where a finite number of heterogeneous capacity-constrained sellers compete for a finite number of homogeneous buyers, by posting prices. This "directed search" model is known to admit symmetric equilibria; yet, uniqueness has proved elusive. This study makes two contributions: a substantive contribution is to establish uniqueness of symmetric equilibrium; a methodological contribution is to develop a tool based on directional derivatives to characterize equilibrium.


NOTICE: this is the author’s version of a work that was accepted for publication in Journal of Economic Theory. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Journal of Economic Theory, volume 151, 2014. DOI: 10.1016/j.jet.2013.11.004


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