Shaimaa Sedek
Author directory2026
OBLIQ-IR: Training a Dense Retriever for Oblique Queries
Mahmoud Abdalla | Abdelrahman Abdallah | Shaimaa Sedek | Adam Jatowt
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Mahmoud Abdalla | Abdelrahman Abdallah | Shaimaa Sedek | Adam Jatowt
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
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.