英文标题：
《Symmetry restoration by pricing in a duopoly of perishable goods》
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作者：
Su Do Yi, Seung Ki Baek, Guillaume Chevereau, and Eric Bertin
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最新提交年份：
2015
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英文摘要：
  Competition is a main tenet of economics, and the reason is that a perfectly competitive equilibrium is Pareto-efficient in the absence of externalities and public goods. Whether a product is selected in a market crucially relates to its competitiveness, but the selection in turn affects the landscape of competition. Such a feedback mechanism has been illustrated in a duopoly model by Lambert et al., in which a buyer\'s satisfaction is updated depending on the {\\em freshness} of a purchased product. The probability for buyer $n$ to select seller $i$ is assumed to be $p_{n,i} \\propto e^{ S_{n,i}/T}$, where $S_{n,i}$ is the buyer\'s satisfaction and $T$ is an effective temperature to introduce stochasticity. If $T$ decreases below a critical point $T_c$, the system undergoes a transition from a symmetric phase to an asymmetric one, in which only one of the two sellers is selected. In this work, we extend the model by incorporating a simple price system. By considering a greed factor $g$ to control how the satisfaction depends on the price, we argue the existence of an oscillatory phase in addition to the symmetric and asymmetric ones in the $(T,g)$ plane, and estimate the phase boundaries through mean-field approximations. The analytic results show that the market preserves the inherent symmetry between the sellers for lower $T$ in the presence of the price system, which is confirmed by our numerical simulations.
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中文摘要：
竞争是经济学的一个主要原则，原因是在没有外部性和公共品的情况下，完全竞争均衡是帕累托有效的。一种产品是否在市场中被选中，对其竞争力至关重要，但这种选择反过来又会影响竞争格局。Lambert等人在一个双寡头模型中说明了这种反馈机制，在该模型中，买方的满意度根据购买产品的{em新鲜度}进行更新。假设买方$n$选择卖方$i$的概率为$p{n，i}\\Proppto e{S{n，i}/T}$，其中$S{n，i}$是买方的满意度，$T$是引入随机性的有效温度。如果$T$下降到临界点$T_c$以下，系统将从对称阶段过渡到非对称阶段，在该阶段中，两个卖方中只有一个被选中。在这项工作中，我们通过加入一个简单的价格体系来扩展模型。通过考虑贪婪因子$g$来控制满意度如何依赖于价格，我们论证了在$（T，g）$平面上除了对称和非对称相位之外，还存在一个振荡相位，并通过平均场近似估计相位边界。分析结果表明，在价格体系存在的情况下，市场保持了低价T$卖家之间固有的对称性，这一点已被我们的数值模拟所证实。
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分类信息：

一级分类：Quantitative Finance        数量金融学
二级分类：Economics        经济学
分类描述：q-fin.EC is an alias for econ.GN. Economics, including micro and macro economics, international economics, theory of the firm, labor economics, and other economic topics outside finance
q-fin.ec是econ.gn的别名。经济学，包括微观和宏观经济学、国际经济学、企业理论、劳动经济学和其他金融以外的经济专题
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一级分类：Physics        物理学
二级分类：Physics and Society        物理学与社会
分类描述：Structure, dynamics and collective behavior of societies and groups (human or otherwise). Quantitative analysis of social networks and other complex networks. Physics and engineering of infrastructure and systems of broad societal impact (e.g., energy grids, transportation networks).
社会和团体（人类或其他）的结构、动态和集体行为。社会网络和其他复杂网络的定量分析。具有广泛社会影响的基础设施和系统（如能源网、运输网络）的物理和工程。
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