Feature Construction Based on Closedness Properties Is Not That Simple

Feature construction has been studied extensively, including for 0/1 data samples. Given the recent breakthrough in closedness-related constraint-based mining, we are considering its impact on feature construction for classification tasks. We investigate the use of condensed representations of frequent itemsets (closure equivalence classes) as new features. These itemset types have been proposed to avoid set counting in difficult association rule mining tasks. However, our guess is that their intrinsic properties (say the maximality for the closed itemsets and the minimality for the δ-free itemsets) might influence feature quality. Understanding this remains fairly open and we discuss these issues thanks to itemset properties on the one hand and an experimental validation on various data sets on the other hand.