OBLIQ-IR: Training a Dense Retriever for Oblique Queries

Mahmoud Abdalla, Abdelrahman Abdallah, Shaimaa Sedek, Adam Jatowt


Abstract
Oblique retrieval, recently introduced by OBLIQ-Bench, asks a retriever to surface documents whose relevance is determined by a latent attribute (an implicit stance, an analogous reasoning technique, an authorial fingerprint, or a vague tip-of-the-tongue recollection) that has little or no surface expression in the document. State-of-the-art dense encoders and agentic search pipelines built around frontier language models leave a large first-stage bottleneck on these tasks, while the same language models reliably verify relevance when shown candidates. We address this with OBLIQ-IR, a single-vector dense retriever whose training mixture combines per-mechanism synthetic queries with a new form of cross-model supervision: kNN-graph distillation from a frozen authorship encoder, which transfers a style-versus-topic inductive bias into the student. A 3B retriever fine-tuned reaches 0.211 NDCG@10 on Writing-Style, 0.171 on Math, 0.177 on Twitter, and 0.281 on Congress, improving over the GPT-5.2 Multi-Hop Agent by 0.010 to 0.098 NDCG@10 and over Gemini-2-Embedding by 0.027 to 0.222 NDCG@10 on every reported task.
Anthology ID:
2026.emnlp-main.494
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:
11348–11369
Language:
URL:
https://aclanthology.org/2026.emnlp-main.494/
DOI:
Bibkey:
Cite (ACL):
Mahmoud Abdalla, Abdelrahman Abdallah, Shaimaa Sedek, and Adam Jatowt. 2026. OBLIQ-IR: Training a Dense Retriever for Oblique Queries. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 11348–11369, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
OBLIQ-IR: Training a Dense Retriever for Oblique Queries (Abdalla et al., EMNLP 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.emnlp-main.494.pdf