Learned Sparse Lexical Representations for Large-scale Authorship Attribution

Jian Zhu, Su Yuan, Changbing Yang


Abstract
Authorship attribution aims to determine whether a query text and a candidate document are written by the same author. %While dense embeddings are effective, recent work suggests that low-dimensional representations limit encoding capacity. We investigate high-dimensional learned sparse representations (LSR) and multi-vector retrieval for authorship attribution. We further propose Sparse ColBERT (SparCol), a late-interaction sparse lexical reranking model. To address the memory cost of vocabulary-size embeddings, we develop fused Triton kernels that can reduce peak memory usage by 5 11 times over the baseline torch implementation. Extensive experiments show that LSR can outperform dense embeddings in both single-genre and cross-genre settings, whereas improves reranking performance over single-vector models only in single-genre settings due to lexical matching bias. In addition to token-based embeddings, we also explore Lexicon-based embeddings that score clusters of tokens, which is competitive with the vocabulary-based LSR with reduced dimensions. We conduct interpretability analysis of LSRs, showing that they allow for a more transparent scoring process.
Anthology ID:
2026.findings-emnlp.400
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
8455–8482
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URL:
https://aclanthology.org/2026.findings-emnlp.400/
DOI:
Bibkey:
Cite (ACL):
Jian Zhu, Su Yuan, and Changbing Yang. 2026. Learned Sparse Lexical Representations for Large-scale Authorship Attribution. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 8455–8482, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Learned Sparse Lexical Representations for Large-scale Authorship Attribution (Zhu et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.400.pdf