Revisiting Sparsity Constraint Under High-Rank Property in Partial Multi-Label Learning
Chongjie Si, Yidan Cui, Fuchao Yang, Xiaokang Yang, Wei Shen
TL;DR
This work revisits Partial Multi-Label Learning (PML) by challenging the common assumption that noise is sparse and true labels are low-rank; real-world label matrices are typically full-rank, creating a conflict in prior methods. The authors propose Schirn, a method that enforces sparsity on the noise label matrix while preserving a high-rank property for the predicted label matrix, achieved via a convex-relaxed objective that combines a nuclear-norm term and an L1 penalty, solved with an Augmented Lagrangian framework. Theoretical support is provided by a rank-perturbation argument showing that sparse noise preserves high rank under perturbations, and extensive experiments on 11 datasets (5 real-world, 6 synthetic) demonstrate that Schirn outperforms state-of-the-art PML methods across multiple metrics. The work introduces a principled perspective on the sparsity-rank relationship in PML, with practical impact on disambiguating noisy candidate labels while maintaining rich label structure; future work includes extending Schirn to end-to-end deep learning architectures.
Abstract
Partial Multi-Label Learning (PML) extends the multi-label learning paradigm to scenarios where each sample is associated with a candidate label set containing both ground-truth labels and noisy labels. Existing PML methods commonly rely on two assumptions: sparsity of the noise label matrix and low-rankness of the ground-truth label matrix. However, these assumptions are inherently conflicting and impractical for real-world scenarios, where the true label matrix is typically full-rank or close to full-rank. To address these limitations, we demonstrate that the sparsity constraint contributes to the high-rank property of the predicted label matrix. Based on this, we propose a novel method Schirn, which introduces a sparsity constraint on the noise label matrix while enforcing a high-rank property on the predicted label matrix. Extensive experiments demonstrate the superior performance of Schirn compared to state-of-the-art methods, validating its effectiveness in tackling real-world PML challenges.
