In this paper we develop a model of the exchange rate. The existence of transactions costs introduces an important non-linearity. Agents have different beliefs about the future exchange rate. We show that this simple model creates great complexity in the market which is characterised by the fact...

We analyse the workings of a simple non-linear exchange rate model in which agents hold different beliefs about the underlying model. We distinguish between chartists and fundamentalists . The non-linearities in the model originate from transactions costs and from the existence of non-linear...

We study environmental policy in an economy-ecology model featuring multiple deterministic stable steady-state ecological equilibria. The economy-ecology does not settle in either of the deterministic steady states as the environmental system is hit by random shocks. Individual live for two...

This profile of Jean-Michel Grandmont is based on several interviews we had with him between September 2016 and April 2017. The interviews took place at our CREST offices, located at that time in Malakoff, just south of Paris. The objective of the profile is twofold. First, we trace the career...

We study the environmental and economic effects of public abatement in the presence of multiple stable steady-state ecological equilibria. Under shallow-lake dynamics (SLD), the isocline for the stock of pollution features two stable branches, a good and a bad one. Assuming that the ecology is...

This paper introduces dynamics in the R&D to innovation and innovation to productivity relationships, which have mostly been estimated on cross-sectional data. It considers four nonlinear dynamic simultaneous equations models that include individual effects and idiosyncratic errors correlated...

This paper studies dynamics of endogenous business cycles and exchange rate volatility in a small open economy. Without market imperfections, domestic price and wage adjustments respond sluggishly to disequilibrium situations on real domestic markets while prices on international capital markets...

We develop an algorithm for solving a large class of nonlinear high-dimensional continuous-time models in finance. We approximate value and policy functions using deep learning and show that a combination of automatic differentiation and Ito's lemma allows for the computation of exact...

We develop a simple model of the exchange rate in which agents optimize their portfolio and use different forecasting rules. They check the profitability of these rules ex post and select the more profitable one. This model produces two kinds of equilibria, a fundamental and a bubble one. In a...

We study two dimensions of complexity that may interfere with individual choice. The first one is object complexity, which corresponds to the difficulty in evaluating any given alternative in a choice set. The second dimension is composition complexity, which increases when suboptimal...