Note that the remaining features whose weights we sum up (line 4 in Algorithm 2) are primitive and conjunctive features that relate to f ∈ x − x c , which appear less frequently than f ∈ x c in the training data.
when we apply our algorithm to classifiers with the sparse solution (e.g., SVM-HKEs or 1 -LLMs), |x c | can be much smaller than the theoretical expectation (Eq.