Before revision:  In the spirit of the Fundamental Theorem of Asset Pricing , it is shown that there is equivalence between the absence of arbitrages of the first kind  and the existence of a strictly positive process that acts as a local martingale deflator on nonnegative wealth processes.
After revision:  In the spirit of the Fundamental Theorem of Asset Pricing , it is shown that there is equivalence between the absence of arbitrages of the first kind (a weak viability condition) and the existence of a strictly positive process that acts as a local martingale deflator on nonnegative wealth processes.