Characterizations and Algorithms of Extensionsfor CADL and QDL

Receatly, Giordano and Martelli ( 1994) proposed two new cumu- lative variants of Reiter's default logic (DL) : Commitment to Assumptions Default Logic (CADL) and Quasi-Default Logic (QDL). They have only given quasi-inductive characterizations of extensions for the two variants. In this paper, finite characteri- zatioas of extensions for CADL and QDL by applying notions of (joint) compatibility are presented respectively. And corresponding algorithms and complexity results for reasoning are obtairfed.