Variations and Absolute Continuity of Set Functions on T_∞-tribe

some properties of the inclusion variation and the disjoint variation of set functions on T_∞-tribe are studied in detail. The absolute continuity and singularity of set functions on T_∞-tribe are discussed. The triangular norms T_∞ and S_∞ are considered as the operators of intersection and union between the fuzzy sets. As a result, some important conclusions about the variations and absolute continuity of set functions on T_∞-tribe are obtained such as the superadditivity of inclusion variation, the relation between the variations and the equivalence proposition of absolute continuity of set functions on T_∞-tribe. In addition, two small mistakes about T_∞-measure are pointed out by the counterexamples and are revised.