Before revision: We investigate different notions of arbitrage in a multiple-priors setting in discrete time . We revisit the so-called quasi-sure no-arbitrage condition and prove a geometric and a quantitative version of it .
After revision: We investigate different notions of arbitrage in a multiple-priors setting, we propose a new characterisation of the condition of quasi-sure no-arbitrage condition and prove a geometric and a quantitative version of it .