Autour d'un théorème de Tsirelson sur des filtrations browniennes et non browniennes
On étend aux martingales bi-browniennes la formule de Itô et les inégalités de Burkholder-Gundy. On en déduit une démonstration probabiliste des inégalités de norme géométriques pour les fonctions bi-harmoniques sur le bi-disque.
Our purpose is to investigate properties for processes with stationary and independent increments under -expectation. As applications, we prove the martingale characterization of -Brownian motion and present a pathwise decomposition theorem for generalized -Brownian motion.
Asymmetric or partial information in financial markets may be represented by different filtrations. We consider the case of a larger filtration F – the natural filtration of the “model world” – and a subfiltration that represents the information available to an agent in the “real world”. Given a price system on the larger filtration that is represented by a martingale measure Q and an associated numeraire S, we show that there is a canonical and nontrivial numeraire Ŝ such that the price system...