Before revision: The absence of arbitrages of the first kind, a weakening of the ``No Free Lunch with Vanishing Risk'' condition, is analyzed in a general semimartingale financial market model . 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: The absence of arbitrages of the first kind, a weakening of the ``No Free Lunch with Vanishing Risk'' condition, is analyzed in a general semimartingale financial market model , 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.