Reactivating Test-Time Scaling for Plane Geometry Problem Solving

Xiaoqiang Kang, Shengen Wu, Maizhen Ning, Xiaobo Jin, Kaizhu Huang, Yutao Yue, Xiaowei Huang, Qiufeng Wang


Abstract
Plane geometry problem (PGP) solving has become a critical benchmark for multimodal reasoning because it requires accurate visual perception and precise multi-step symbolic deduction. Although test-time scaling (TTS) has demonstrated remarkable success in general mathematical reasoning, it fails to scale effectively under the symbolic-program paradigm for plane geometry. We identify two key obstacles: limited reasoning diversity induced by rigid symbolic programs and insufficient explicit visual grounding before symbolic deduction. To address these issues, we propose Multi-Trace Synthesis (MTS), which converts each symbolic program into heterogeneous reasoning traces, including executable Python scripts and CoT-augmented variants. We further propose Perception-Augmented (PA) training, which parses diagrams into structured semantic clauses before deduction, and Consensus-Guided Multi-Trace Ensemble (CG-MTE) for efficient self-adaptive inference. Experiments on three geometry benchmarks show that our method consistently improves PGP-solving across model scales and achieves strong performance against both general-purpose MLLMs and specialized geometry solvers. Under test-time scaling, CG-MTE achieves a comparable accuracy to high-budget self-consistency while reducing sampling cost by up to 8×. Code and data are publicly available at https://github.com/Jason8Kang/ReTTS-PGPS.
Anthology ID:
2026.emnlp-main.487
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:
11193–11211
Language:
URL:
https://aclanthology.org/2026.emnlp-main.487/
DOI:
Bibkey:
Cite (ACL):
Xiaoqiang Kang, Shengen Wu, Maizhen Ning, Xiaobo Jin, Kaizhu Huang, Yutao Yue, Xiaowei Huang, and Qiufeng Wang. 2026. Reactivating Test-Time Scaling for Plane Geometry Problem Solving. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 11193–11211, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Reactivating Test-Time Scaling for Plane Geometry Problem Solving (Kang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.487.pdf