We present conditions for the emergence of singularities in DGE models. We distinguish between slow-fast and impasse singularity types, review geometrical methods to deal with both types of singularity and apply them to DGE dynamics. We find that impasse singularities can generate new types of...

In this paper we consider the entry and exit of firms in a Ramsey model with capital and an endogenous labour supply. At the firm level, there is a fixed cost combined with increasing marginal cost, which gives a standard U-shaped cost curve with optimal firm size. The costs of entry (exit) are...

We develop a simple Ramsey model with numerous Cournotian industries where entry generates an endogenous markup. The model produces two different regimes: a monopoly and an oligopoly one. We provide a rigorous study of non-smooth dynamics and we also analyse the global dynamics of the model,...

This paper argues that the cross-sectional approach to durations is essential to understand nominal rigidity because this captures the fact that price-spells are generated by firms' price-setting behavior. Since the distribution of durations is dominated by a proliferation of short contracts,...

This paper adopts the Impulse-Response methodology to understand inflation persistence. It has often been argued that existing models of pricing fail to explain the persistence that we observe. We adopt a common general framework which allows for an explicit modelling of the distribution of...

We show a simple way to introduce monopolistic competition in a general equilibrium model where prices are fully .exible, the velocity of money is variable and cash-in-advance (CIA) constraints occasionally bind.We establish the conditions under which money has real effects and demonstrate that...