SHARP: Span-level Hallucination Annotation for Reasoning Paths in Generated Mathematical Solutions

Timofey Garaev, Makar Gorokhovik, Alexey Korotkov, Maksim Savkin, Iurii Vizilter, Andrey Savchenko


Abstract
We introduce SHARP, a compact, span-annotated dataset for hallucination detection in model-generated mathematical solutions. Unlike existing resources that rely on coarse step-level labels, SHARP provides fine-grained, span-level annotations generated through an automated pipeline. Our methodology synthesizes realistic reasoning traces with precise error markup, enabling the production of high-fidelity training data with minimal computational overhead. Despite being 10–30 tim smaller than existing open-source datasets, a 1.5B PRM fine-tuned on SHARP achieves state-of-the-art performance on ProcessBench.
Anthology ID:
2026.findings-emnlp.500
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:
10470–10487
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.500/
DOI:
Bibkey:
Cite (ACL):
Timofey Garaev, Makar Gorokhovik, Alexey Korotkov, Maksim Savkin, Iurii Vizilter, and Andrey Savchenko. 2026. SHARP: Span-level Hallucination Annotation for Reasoning Paths in Generated Mathematical Solutions. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 10470–10487, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
SHARP: Span-level Hallucination Annotation for Reasoning Paths in Generated Mathematical Solutions (Garaev et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.500.pdf