We incorporate the behaviour of tax evasion into the standard two-dimensional Ising model and augment it by providing policy-makers with the opportunity to curb tax evasion via an appropriate enforcement mechanism. We find that tax evasion may vary greatly over time if no measures of control are...

The 2-spin Ising model in statistical mechanics and the 2×2 normal form game in game theory are compared. All configurations allowed by the second are recovered by the first when the only concern is about Nash equilibria. But it holds no longer when Pareto optimum considerations are introduced...

In this Note a social network model for opinion formation is proposed in which a person connected to q partners pays an attention 1/q to each partner. The mutual attention between two connected persons i and j is taken equal to the geometric mean 1/qiqj. Opinion is represented as usual by an...

Since its introduction in 2000, the Sznajd model has been assumed to simulate a democratic community with two parties. The main flaw in this model is that a Sznajd system freezes in the long term in a non-democratic state, which can be either a dictatorship or a stalemate configuration. Here we...

"Sociophysicists" provoke sociologists: new computer simulation models explain the mechanism which makes moderate individuals radicalise. It is sufficient to be a little self-confident and to keep contact with a few extremists to let extremists win a majority in society.

A contribution to the JASSS forum, in reaction to the paper in FASZ about our model of extremism

Opinion Dynamics models can be, for most of them, divided between discrete and continuous. They are used in different circumstances and the relationship between them is not clear. Here we will explore the relationship between a model where choices are discrete but opinions are a continuous...

In this article, we use a kinetic description to study the effect of different psychologies on the evolution of the opinion with respect to a binary choice, in a closed group. We show that the interaction between individuals with different reactions regarding the exchange of opinion induces...

We study the effect of inflexible agents on two state opinion dynamics. The model operates via repeated local updates of random grouping of agents. While floater agents do eventually flip their opinion to follow the local majority, inflexible agents keep their opinion always unchanged. It is a...

Public debates driven by incomplete scientific data where nobody can claim absolute certainty, due to the current state of scientific knowledge, are studied. The cases of evolution theory, global warming and H1N1 pandemic influenza are investigated. The first two are of controversial impact...