This paper presents a small-scale agent-based extension of the so-called neo-Kaleckian model. The aim is to investigate the emergence of Harrodian instability in decentralized market economies. We introduce a parsimonious microfoundation of investment decisions. Agents have heteroge- neous expectations about demand growth and set idiosyncratically their investment expendi- tures. Interactions occur through demand externalities. We simulate the model under different scenarios. First, when heterogeneity is ruled out, Harrodian instability is showed to emerge as for the aggregate model. Instead, when heterogeneity is accounted for, a stable dynamics with endogenous fluctuations arises. At the same time, in this second scenario, all the Keynesian implications are preserved, including the presence of macroeconomic paradoxes. Sensitivity analysis confirms the general robustness of our results and the logical consistency of the model.

中文翻译：

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去中心化经济中的 Harrodian 不稳定性：基于代理的方法

本文提出了所谓的新卡莱克模型的基于代理的小规模扩展。目的是调查去中心化市场经济中出现的 Harrodian 不稳定性。我们介绍了一个简约的投资决策微观基础。代理商对需求增长有着不同的预期，并以独特的方式设定他们的投资支出。相互作用通过需求外部性发生。我们在不同场景下模拟模型。首先，当排除异质性时，哈罗德的不稳定性就出现在聚合模型中。相反，当考虑到异质性时，会出现具有内生波动的稳定动态。同时，在第二种情景中，所有凯恩斯主义的含义都保留了下来，包括宏观经济悖论的存在。