Greedy Matching Aggregation for Soft Contrastive Learning in Multi-Label Text Classification

Ryoma Kobayashi, Jiyi Li


Abstract
Multi-label text classification is important for organizing large document collections, but correlated labels and skewed label distributions make representation learning difficult. Existing multi-label contrastive methods usually define pairwise supervision from label overlap, resulting in a coarse signal limited to observed shared labels. We propose Greedy Matching Aggregation Soft Contrastive Learning (GMA-SCL), which constructs contrastive targets for MLTC by greedily matching label texts and incorporating label importance weighting. The resulting reference distribution is sharpened to emphasize highly similar candidate documents while preserving graded supervision from moderately similar ones. Experiments on AAPD, Reuters-21578, and UK-LEX show that GMA-SCL improves Macro-F1 over existing multi-label contrastive baselines while maintaining competitive Micro-F1 and Hamming Loss. Our code is available at https://github.com/koba-84/gma-scl.
Anthology ID:
2026.findings-aacl.62
Volume:
Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026
Month:
November
Year:
2026
Address:
Hengqin, China
Editors:
Yue Zhang, Ruifeng Xu, Ayu Purwarianti, Tong Rong, Jun Suzuki
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1222–1235
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URL:
https://aclanthology.org/2026.findings-aacl.62/
DOI:
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Cite (ACL):
Ryoma Kobayashi and Jiyi Li. 2026. Greedy Matching Aggregation for Soft Contrastive Learning in Multi-Label Text Classification. In Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026, pages 1222–1235, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
Greedy Matching Aggregation for Soft Contrastive Learning in Multi-Label Text Classification (Kobayashi & Li, Findings 2026)
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https://aclanthology.org/2026.findings-aacl.62.pdf