UTokyo Tsuruoka Lab at SemEval-2026 Task 9: Efficient Single Forward Pass Inference for Multi-Label Polarization Classification

Howard Tangkulung, Yoshimasa Tsuruoka


Abstract
Detecting and interpreting polarized online content is increasingly crucial as online platforms become central to public information exchange. We present an efficient adaptation of large language models for multi-label polarization classification in SemEval-2026 Task 9: Detecting Multilingual, Multicultural and Multievent Online Polarization. Our single-forward-pass inference method outperforms baseline multi-step decoding approaches for multi-label classification by reducing error propagation while improving inference efficiency. Beyond performance and efficiency analysis, we investigate the cross-lingual transferability of the system, observing statistically significant generalization within language families, a result that offers a practical path for low-resource language adaptation. Our system ranked 1st in 8 languages for Subtask 1 and 6 languages for Subtask 2, and placed in the top 5 for 16 out of 22 languages across both subtasks.Overall, we provide a simple, effective, and efficient solution for multilingual polarization classification.
Anthology ID:
2026.semeval-1.211
Volume:
Proceedings of the 20th International Workshop on Semantic Evaluation (2026)
Month:
July
Year:
2026
Address:
San Diego, California, USA
Editors:
Ekaterina Kochmar, Debanjan Ghosh, Kai North, Mamoru Komachi
Venues:
SemEval | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
1641–1651
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URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.211/
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Bibkey:
Cite (ACL):
Howard Tangkulung and Yoshimasa Tsuruoka. 2026. UTokyo Tsuruoka Lab at SemEval-2026 Task 9: Efficient Single Forward Pass Inference for Multi-Label Polarization Classification. In Proceedings of the 20th International Workshop on Semantic Evaluation (2026), pages 1641–1651, San Diego, California, USA. Association for Computational Linguistics.
Cite (Informal):
UTokyo Tsuruoka Lab at SemEval-2026 Task 9: Efficient Single Forward Pass Inference for Multi-Label Polarization Classification (Tangkulung & Tsuruoka, SemEval 2026)
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https://preview.aclanthology.org/ingest-acl-workshops/2026.semeval-1.211.pdf
Supplementarymaterial:
 2026.semeval-1.211.SupplementaryMaterial.zip