A Proof of Determinacy in the New-Keynesian Sticky Wages and Prices Model

The paper is concerned with determinacy in a version of the New-Keynesian model that integrates imperfect competition and nominal price and wage setting on goods and labour markets. The model is reformulated with an explicit period of arbitrary length and shown to remain well-defined as the period shrinks to zero. The 4×4 constituent matrix of the model?s continuous-time counterpart is mathematically tractable and its determinacy results carry over to the period model at least if the period is sufficiently short. This being understood, it is proved that determinacy is (essentially) ensured if an extended Taylor principle requirement is met.