Recently, Giordano and Martelli (1994) proposed two newcumulative variants of Reiters default logic (DL): Commitment toAssumptions Default Logic (CADL) and Quasi-Default Logic (QDL). Theyhave only given quasi-inductive characterizations of extensions for thetwo variants. In this paper, finite characterizations of extensions forCADL and QDL by applying notions of (joint) compatibility are presentedrespectively. And corresponding algorithms and complexity results forreasoning are obtained.