Inspired by the recent literature on aggregation theory, we aim at relating the long range correlation of the stocks return volatility to the heterogeneity of the investors' expectations about the level of the future volatility. Based on a semi-parametric model of investors' anticipations, we...

We modify the usual percolation theory (PT) by subtituting single particles which occupy sites on a two-dimensional square lattice, by pairs of particles linked by strings whose maximum length is a multiple of the basic lattice spacing. The crossing of random length strings of the pairs leads to...