In the standard bootstrap percolation on the d-dimensional grid Gnd, in the initial position each of the nd sites is occupied with probability p and empty with probability 1−p, independently of the state of every other site. Once a site is occupied, it remains occupied for ever, while an empty...

We study the patterns formed by adding N sand grains at a single site in the abelian sandpile model on an infinite square lattice, when in the initial configuration all sites have same height. When this height is 2, stable heights being 0–3, we show that the perturbed region is a square, whose...

This paper studies the effects of local trade networks on the spatial distribution of employment in a model that allows for effective demand externalities as well as home bias. It is shown that, if labor can be hired in continuous quantities, then the long run spatial distribution of employment...

The investigation of traffic flow problems has a long tradition and various methods and approaches have been applied. In this review we focus on statistical mechanics and nonequilibrium aspects. It is shown that many properties of traffic flow can be modelled successfully by using rather simple...