“…Recently, several novel properties of financial prices series have been documented, such as the negative auto-correlation of price changes at short times, the abnormal diffusion of prices [17][18][19], the long-auto correlation of volatility [20], the long-memory process of sign of orders [21,22], the property that implicitly underlies the present considerations as financial multifractality [23,24], large price changes characterized by the gap of a limit order book (containing no quotes between prices) [25], the existence of endogenous feedback mechanisms that are well characterised by the self-excited Hawkes model [26], rich market impact dynamics revealed in nonlinear price changes caused by submitted orders [27][28][29], and the Fokker-Plank description for the queue dynamics of the order book [30].…”