Func-R1: Incentivizing Mathematical Function Reasoning in Multimodal Large Language Models

Mingze Yin, Xiaohan Wang, Dian Li, Yao Haichao, Yilin Zhao, Youjun Chen, Sinbadliu, Jintai Chen, Yiheng Zhu, Chang-Yu Hsieh, Aimin Pan


Abstract
Performing deliberate mathematical reasoning in visual contexts is a hallmark of expert-level Multimodal Large Language Models (MLLMs) and requires a sophisticated synthesis of perceptual grounding and symbolic logic. However, in the realm of mathematical functions, our investigation reveals a critical *modality interference phenomenon*: even advanced models, while performing textual computational reasoning, tend to disregard or misinterpret essential visual cues. To address this challenge, we propose **Func-R1**, which synergistically harmonizes precise visual perception and rigorous logical reasoning. Concretely, built upon an explicitly decoupled architecture, we employ a hierarchical post-training framework to progressively identify critical visual evidence and conduct in-depth theoretical reasoning. Furthermore, the *Perception-Aligned Theoretic Optimization (PATO)* strategy is proposed to steer policy updating towards internalizing fundamental theoretical properties while dynamically rectifying heterogeneous visual information throughout the reasoning process. Extensive experiments across diverse benchmarks demonstrate that Func-R1 delivers the optimal performance among open-source MLLMs, even surpassing GPT-5 with an 8.4% improvement on MathVerse’s function-oriented tasks.
Anthology ID:
2026.findings-emnlp.1906
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
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
40616–40632
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URL:
https://aclanthology.org/2026.findings-emnlp.1906/
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Cite (ACL):
Mingze Yin, Xiaohan Wang, Dian Li, Yao Haichao, Yilin Zhao, Youjun Chen, Sinbadliu, Jintai Chen, Yiheng Zhu, Chang-Yu Hsieh, and Aimin Pan. 2026. Func-R1: Incentivizing Mathematical Function Reasoning in Multimodal Large Language Models. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 40616–40632, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Func-R1: Incentivizing Mathematical Function Reasoning in Multimodal Large Language Models (Yin et al., Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.1906.pdf