Robust No Arbitrage Condition for Continuous-time Models with Transaction Costs

AbstractWe extend the Robust No Free Lunch (RNFL) theorem formulated for discrete-time models with proportional transaction costs to general continuous-time settings. We prove that the (RNFL) condition is equivalent to the existence of a strictly consistent price system, i.e. a martingale evolving in the interior of the solvency cone of all portfolio positions which can be changed into positive ones paying transaction costs.