this paper.

We propose a stochastic dynamic model of migration and economic aggregation in a system of employed (immobile) and unemployed (mobile) agents which respond to local wage gradients. Dependent on the local economic situation, described by a production function which includes cooperative effects, employed agents can become unemployed and vice versa. The spatiotemporal distribution of employed and unemployed agents is investigated both analytically and by means of stochastic computer simulations. We find the establishment of distinct economic centers out of a random initial distribution. The evolution of these centers occurs in two different stages: (i) small economic centers are formed based on the positive feedback of mutual stimulation/cooperation among the agents, (ii) some of the small centers grow at the expense of others, which finally leads to the concentration of the labor force in different extended economic regions. This crossover to large-scale production is accompanied by an increase in the unemployment rate. We observe a stable coexistence between these regions, although they exist in an internal quasistationary non-equilibrium state and still follow a stochastic eigendynamics.

Abstract This paper proposes a multiactivity generalisation of the Nelson–Winter model, or the NW model, in order to turn the attention of evolutionary minded economists toward specialisation and exchange, the emergence of markets for intermediate goods, the specialisation of R&D, and other issues of multisectoral growth and development. The argument and the solution is presented in four steps. First, there is a discussion of some practical difficulties and core theoretical problems in relation to the standard NW model of Schumpeterian competition. The conclusion is that this model gives an ad hoc solution to the tendency of evolutionary models to produce monopoly and that is has not really confronted the ‘knife-edge ’ problems of the underlying Leontief technology. Thus there is still a need to confront what may be called the diversity paradox and the Leontief technology paradox of evolutionary modelling. Second, the paper develops a condensed version of the NW model that serves to highlight the theoretical problems and as a platform for the proposed generalisation. This version of the NW model, the LNW model, includes only labour and knowledge. With given technologies the LNW model shows standard replicator dynamics while it can also be used as a testbed for exploring different R&D regimes. Third, the bare bones of the multiactivity generalisation of the NW model, the MNW model, is presented. This presentation starts from firms

Abstract: Modellers have had to wrestle with an unavoidable trade-off between the demand of a general theoretical approach and the descriptive accuracy required to model a particular phenomenon. A new class of simulation models has shown to be well adapted to this challenge, basically by shifting outwards this trade-off: So-called agent-based models (ABMs henceforth) are increasingly used for the modelling of socio-economic developments. Our paper deals with the new requirements for modelling entailed by the necessity to focus on qualitative developments, pattern formation, etc. which is generally highlighted within Neo-Schumpeterian Economics and the possibilities given by ABMs. 1 1.

The article discusses recent advances and future challenges in innovation studies. First, it separately considers four main strands of research, studying innovation at the organizational, systemic, sectoral and macroeconomic levels. Then, considering the field as a whole, the article points to the existence of important neglected topics and methodological challenges for future research. In fact, several fundamental issues are still unexplored, such as the co-evolution between technological and institutional change; the role of demand; and the impacts of innovation on individual and collective welfare. There are also important methodological challenges, such as the need for more systematic interactions between the different levels of analysis; the importance of an interdisciplinary approach to the study of technological and institutional changes; and the search for a combination of contingent explanations based on case studies with general analytical results based on econometric and formal models.

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Technological diffusion patterns and their effects on industrial dynamics

The report deals with the reconstruction and further development of the models of industrial dynamics developed by Nelson and Winter and summarised in their famous 1982-book. The basic idea underlying the Nelson and Winter models is that a verbal account of Schumpeterian competition can naturally be transformed into a description of a computational process in which firms not only make short-term production decisions and investment decisions but also performs a search for new technologies. The latter search is successful in a probabilistic manner, and its successes and failures determine an evolutionary process of the industry. Although the simulation models of Nelson and Winter have played a central role the ‘take-off ’ of evolutionary economics, they have never been fully documented and their differences have never been explored. The resulting problems are obvious for students who start from Nelson’s and Winter’s most famous accounts, but even for researchers with a full collection of the underlying research papers, the situation is quite confusing. The report tries to make things easier by presenting overviews of the structure of Nelson and Winter models as well as fully implemented versions of their simulation models –

The paper presents a model of endogenous growth in which firms are modeled as boundedly-rational, locally interacting, agents. Firms produce a homogeneous good employing technologies located in an open-ended technological space and are allowed to either imitate existing similar practices or to locally explore the technological space to find new, more productive, techniques. We first identify sufficient conditions for the emergence of empirically plausible GDP time-series characterized by self-sustained growth. Then, we study the trade-off between individual rationality and collective outcomes by providing an example in which more rational agents systematically perform worse than less rational ones.