Multi-class classification can be solved by decomposing it into a set of binary classification problems according to some encoding rules. Existing works solve these binary classification problems in the original feature space, while it might be suboptimal as different binary classification problems correspond to different positive and negative examples.Multi-class classification can be solved by decomposing it into a set of binary classification problems according to some encoding rules. Existing works solve these binary classification problems in the original feature space, while it might be suboptimal as different binary classification problems correspond to different positive and negative examples.[#item_full_content]