A note on the cumulativity of justified default logic
Grigoris Antoniou · Journal of Experimental & Theoretical Artificial Intelligence · 1998
Cumulativity is an important property of nonmonotonic inference relations because it allows for the safe use of lemmas. This note shows that Justified Default Logic, Lukaszewicz variant of default logic, is cumulative for prerequisite-free default theories, a question that has been open in the literature. The proof is very simple and makes use of an operational interpretation of extensions.