Bringing Clustering to MLL: Weakly-Supervised Clustering for Partial Multi-Label Learning

arXiv cs.LG / 4/13/2026

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Key Points

  • The paper addresses label noise in multi-label learning, focusing on partial multi-label learning (PML) where candidate labels include both relevant and irrelevant options.
  • It argues that standard clustering cannot be directly applied to multi-label settings because clustering yields soft memberships constrained to sum to one, while multi-label assignments are binary and can sum variably.
  • The proposed method, WSC-PML, bridges this mismatch by decomposing the clustering membership matrix into two factors, one preserving clustering constraints and the other preserving multi-label structure.
  • WSC-PML is implemented via a three-stage pipeline: prototype learning from noisy labels, confidence-based construction of weak supervision, and iterative joint optimization with clustering refinement.
  • Experiments across 24 datasets show WSC-PML outperforms six existing state-of-the-art methods across multiple metrics.

Abstract

Label noise in multi-label learning (MLL) poses significant challenges for model training, particularly in partial multi-label learning (PML) where candidate labels contain both relevant and irrelevant labels. While clustering offers a natural approach to exploit data structure for noise identification, traditional clustering methods cannot be directly applied to multi-label scenarios due to a fundamental incompatibility: clustering produces membership values that sum to one per instance, whereas multi-label assignments require binary values that can sum to any number. We propose a novel weakly-supervised clustering approach for PML (WSC-PML) that bridges clustering and multi-label learning through membership matrix decomposition. Our key innovation decomposes the clustering membership matrix \mathbf{A} into two components: \mathbf{A} = \mathbf{\Pi} \odot \mathbf{F}, where \mathbf{\Pi} maintains clustering constraints while \mathbf{F} preserves multi-label characteristics. This decomposition enables seamless integration of unsupervised clustering with multi-label supervision for effective label noise handling. WSC-PML employs a three-stage process: initial prototype learning from noisy labels, adaptive confidence-based weak supervision construction, and joint optimization via iterative clustering refinement. Extensive experiments on 24 datasets demonstrate that our approach outperforms six state-of-the-art methods across all evaluation metrics.