Beyond Bag-of-Words: Generative Structural Regularization for Dense Table Retrieval

WeiJie Liu, Shanshan Chen, Fang Kong


Abstract
Dense retrieval has become the dominant paradigm for large-scale table retrieval. However, existing contrastive retrievers often suffer from bag-of-words degradation: they rely on lexical overlap rather than row–column bindings. To quantify and mitigate this, we propose an adversarial benchmark and a structure-aware retrieval framework. Our benchmark uses "evidence cell" anchoring and a Homologous Structural Swapping mechanism to construct lexically equivalent but structurally invalid negative samples. Our model uses text generation as a structural regularizer for dense table representations. It decouples row and column anchors through orthogonal attention pooling, and employs dynamic masking to encourage autoregressive reconstruction. This process encourages the retrieval representations to retain table content and structure-related cues. Extensive experiments on OTT-QA, NQ-Tables, and our adversarial benchmark demonstrate the effectiveness of our method. It achieves competitive performance on conventional retrieval datasets and substantially improves structural robustness under adversarial settings.
Anthology ID:
2026.emnlp-main.1275
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
29079–29094
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1275/
DOI:
Bibkey:
Cite (ACL):
WeiJie Liu, Shanshan Chen, and Fang Kong. 2026. Beyond Bag-of-Words: Generative Structural Regularization for Dense Table Retrieval. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 29079–29094, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Beyond Bag-of-Words: Generative Structural Regularization for Dense Table Retrieval (Liu et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1275.pdf