The paper investigates the relation between inconsistencytolerant semantics (AR-semantics and Brave-semantics) and a class of default theories in Reiter’s Default Logic called semi-monotonic default theories. We show that any inconsistent knowledge base can be interpreted as a normal closed default theory by means of a polynomial mapping that maps every fact to a default. As result we prove a relation between inference in Reiter’s Default Logic (sceptical and credulous entailment) and inconsistency-tolerant semantics (AR and Brave entailment). In addition, by means of such relation we prove certain properties that will serve as a basis for an anytime algorithm that provides an approximate solution to AR-entailment whenever interrupted.