Modeling Triplet Interactions Beyond Pairwise Attention

Mafizur Rahman, Lijun Qian


Abstract
Standard transformers use pairwise (2D) self-attention, which models only token-to-token interactions. Sparse attention reduces computational cost while keeping the same pairwise structure and cannot capture richer multi-token interactions. Therefore, we propose Higher-Order Block Attention (HOBA), which models explicit triplet interactions using structured 3D attention with block-diagonal unrolling. This design remains computationally efficient while extending attention beyond pairwise relations. Additionally, we demonstrate that cross-block interaction improves HOBA performance by supporting long-range token dependencies beyond triplet modeling. Experiments on ten NLP benchmarks across five tasks show that HOBA consistently outperforms dense and sparse 2D baselines.
Anthology ID:
2026.findings-aacl.101
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
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Publisher:
Association for Computational Linguistics
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Pages:
2010–2026
Language:
URL:
https://aclanthology.org/2026.findings-aacl.101/
DOI:
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Cite (ACL):
Mafizur Rahman and Lijun Qian. 2026. Modeling Triplet Interactions Beyond Pairwise Attention. In Findings of the Association for Computational Linguistics: IJCNLP-AACL 2026, pages 2010–2026, Hengqin, China. Association for Computational Linguistics.
Cite (Informal):
Modeling Triplet Interactions Beyond Pairwise Attention (Rahman & Qian, Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-aacl.101.pdf