Multimodal Large Language Models (MLLMs) often struggle with complex mathematical visual reasoning primarily due to a lack of fine-grained perception, causing initial visual hallucinations to directly trigger cascading reasoning failures. In traditional end-to-end reinforcement learning (RL), sparse rewards fail to decouple perceptual hallucinations from logical missteps, hindering targeted perception optimization. Alternatively, fine-tuning with perception-enhanced CoT data incurs high costs and hallucinations. In this paper, we address these challenges by proposing UniCAR-RL, an annotation-free RL framework. By explicitly decoupling the optimization of perception and reasoning during the training process, it achieves isolation and optimization of both capabilities. Specifically, UniCAR-RL consists of three synergistic branches: 1) a Caption-RL branch that optimizes perception capabilities through verifier-guided reasoning validation; 2) a Reasoning-RL branch that performs logical reasoning based on a gold image description to halt cascading errors; 3) a QA-RL branch that retains native end-to-end alignment to ensure robust question-answering performance. Experiments show that UniCAR-RL substantially improves MLLMs' mathematical and visual reasoning using only raw short-answer data. Furthermore, it demonstrates strong generalization across diverse architectures and scales.
Figures & tables
Figure 1: Motivation of proposed approach. (a) highlights the perception bottleneck of MLLMs in visual mathematical reasoning, but existing RL methods struggle to address it; (b) presents existing perception enhancement methods and their limitations; (c) provides a comparison of error distributions on visual mathematical reasoning tasks.
Figure 2: Overview of UniCAR-RL. It disentangles optimization into three branches: a) the Caption-RL Branch for pure visual perception enhancement, b) the Reasoning-RL Branch for visually-isolated logic optimization, and c) the QA-RL Branch for synergistic end-to-end QA integration.
Model
Venue
WeMath
MathVerse
MathVista
MathVision
Avg.
Close-source Proprietary model
GPT-4o [ 36 ]
68.8
50.2
63.8
30.4
53.4
Claude-3.7-Sonnet [ 37 ]
72.6
52.0
66.8
41.3
58.1
Models based on Qwen3-VL-Instruct
Qwen3-VL-4B [ 38 ]
arXiv 2025
75.0
47.2
73.5
50.1
61.5
Qwen3-VL-8B [ 38 ]
arXiv 2025
79.4
60.8
77.9
52.9
67.8
Table 1: Main results on visual mathematical reasoning benchmarks. The Avg. score is the arithmetic mean over WeMath, MathVerse, MathVista, and MathVision; CVPR-F denotes CVPR Findings. Models marked with ⋆ are evaluated under our setting. Results marked with † are sourced from previous work [ 30 ] . The best value in each column is shown in bold , and the second-best is underlined . For UniCAR-RL ( Verifier ), the Verifier denotes the advanced verifier used during training. This convention applies to all subsequent tables.
Configuration
WeMath
MathVerse
MathVista
MathVision
Avg.
Base model ablations (Verifier: Qwen3.5-35B-A3B)
Qwen2.5-VL-3B (base)
55.9
33.6
59.4
22.5
42.9
+ UniCAR-RL
66.5 (+10.6)
41.8 (+8.2)
68.9 (+9.5)
27.3 (+4.8)
51.1 (+8.2)
Qwen3-VL-4B (base)
75.0
47.2
73.5
50.1
61.5
+ UniCAR-RL
77.8 (+2.8)
50.4 (+3.2)
79.6 (+6.1)
52.9 (+2.8)
65.2 (+3.7)
Verifier ablations
Table 2: Component ablations of UniCAR-RL. We adopt Qwen3-VL-4B (Qwen3.5-35B-A3B) as the default configuration. We then conduct ablations on the base model, parameter scale, and verifier selection. Rows marked (base) denote the pretrained model without UniCAR-RL training and green values report absolute improvement over the corresponding base.
Captioner
Verifier-Solve Accuracy (%) ↑
WeMath
MathVerse
MathVista
MathVision
Avg.
Qwen3-VL-4B (zero-shot)
80.8
62.4
76.6
65.9
71.4
Qwen3-VL-4B + GRPO
82.1 (+1.3)
63.8 (+1.4)
77.8 (+1.2)
67.5 (+1.6)
72.8 (+1.4)
Qwen3-VL-4B + UniCAR-RL
84.9 (+4.1)
65.5 (+3.1)
82.5 (+5.9)
70.8 (+4.9)
75.9 (+4.5)
Table 3: Evaluation results of visual perception. We adopt Gemini 3 Pro as the unified verifier.
Model
ChartQA
HallBench
Models around 4B parameters
Qwen3-VL-4B
83.0
73.7
+UniCAR-RL(Qwen3.5-35B-A3B)
87.9 (+4.9)
75.0 (+1.3)
+UniCAR-RL(Gemini 3 Pro)
89.5 (+6.5)
75.5 (+1.8)
Models around 8B parameters
Qwen3-VL-8B
88.4
75.0
Table 4: Performance comparison on general multimodal benchmarks. HallBench stands for HallusionBench.
Figure 3: Qualitative comparison of mathematical reasoning tasks.
Configuration
WeMath
MathVerse
MathVista
MathVision
Avg.
UniCAR-RL(full)
78.5
51.2
80.4
53.3
65.9
w/o Reasoning-RL Branch
77.2
49.8
78.1
51.4
64.2
w/o Caption-RL Branch (Vanilla GRPO)
76.3
48.5
76.0
50.8
62.8
w/o QA-RL Branch (Base Qwen3-VL-4B)
75.0
47.2
73.5
50.1
61.5
Table 5: Branch ablations of UniCAR-RL. By systematically removing each branch, UniCAR-RL progressively degrades to the standard baseline. The default setup uses Qwen3-VL-4B with the Gemini 3 Pro verifier.
Method
Rollout
Total
Vanilla GRPO (QA-RL)
72.3
297.8
Reasoning-RL
68.4
292.7
Caption-RL
305.1
525.5
UniCAR-RL iteration (sum)
445.8
1116.0 ( ∼ 3.75 × )
Table 6: Training Cost Analysis of UniCAR-RL.
Appendix figures & tables3 assets
Supplementary material from the paper’s appendix.
Appendix
Method
Venue
Backbone
Size
Train
Distill.
Percep.
Reinforcement Learning for Mathematical Reasoning
SRPO [ 19 ]
NeurIPS’25
Qwen2.5-VL
7B/32B
SFT+RL
✓
✓
Vision-R1 [ 21 ]
ICLR’26
Qwen2.5-VL
7B/32B/72B
SFT+RL
✓
✓
MM-Eureka [ 23 ]
TMLR’26
Qwen2.5-VL
7B/32B
Zero-RL
×
✓
R1-VL [ 24 ]
ICCV’25
Qwen2-VL
7B
SFT+RL
×
✓
URSA [ 22 ]
NeurIPS’25
Qwen2.5-Math
8B
SFT+RL
✓
✓
Appendix
Table 7: Comparison of representative methods for multimodal mathematical reasoning. “Train” indicates the training paradigm, where “Zero-RL” denotes direct RL optimization from a pretrained or instruction-tuned model without task-specific cold-start SFT, “SFT+RL” denotes a cold-start supervised stage followed by reinforcement learning, and “–” indicates non-RL methods. “Distill.” indicates whether the method explicitly relies on distilled reasoning traces, teacher-generated supervision, or synthetic high-quality CoT/QA data. “Percep.” denotes whether the method explicitly enhances visual perception, grounding, diagram understanding, or visual reasoning capabilities.
Model
ChartQA
HallBench
V*Bench
HR-Bench 4K
HR-Bench 8K
Qwen3-VL-4B
83.0
73.7
86.4
80.0
73.6
+UniCAR-RL
89.5
75.5
88.5
81.6
76.4
Qwen3-VL-8B
88.4
75.0
88.7
81.2
76.5
+UniCAR-RL
90.6
75.4
90.1
82.8
78.3
Appendix
Table 8: Additional perception results on ChartQA, HallBench, V*Bench and HR-Bench. Gemini 3 Pro is used as the verifier during training by default.
Figure 8: Task-specific prompt templates and output evaluation protocols. Placeholders enclosed in braces are replaced with the corresponding benchmark questions and answer options at inference time.
Recent progress in large-scale reinforcement learning (RL) has notably enhanced the reasoning capabilities of large language models (LLMs), especially in mathematical domains. However, current multimodal LLMs (MLLMs) for mathematical reasoning often rely on one-to-one image-text pairs and single-solution supervision, overlooking the diversity of valid reasoning perspectives and internal reflections. In this work, we introduce MathV-DP, a novel dataset that captures multiple diverse solution trajectories for each image-question pair, fostering richer reasoning supervision. We further propose Qwen-VL-DP, a model built upon Qwen-VL, fine-tuned with supervised learning and enhanced via group relative policy optimization (GRPO), a rule-based RL approach that integrates correctness discrimination and diversity-aware reward functions. Our method emphasizes learning from varied reasoning perspectives and distinguishing between correct yet distinct solutions. Extensive experiments on the MathVista's minitest and Math-V benchmarks demonstrate that Qwen-VL-DP significantly outperforms prior base MLLMs in both accuracy and generative diversity, highlighting the importance of incorporating diverse perspectives and reflective reasoning in multimodal mathematical reasoning.
Wenhao Shi, Zhiqiang Hu, Yi Bin +4
Tongji University, Shanghai, China · National University of Singapore, Singapore · Tencent, Beijing, China +2
Chain-of-Thought (CoT) reasoning has extended from purely linguistic domains to multimodal scenarios; however, existing approaches often treat visual inputs as homogeneous or auxiliary signals, failing to capture the intricate and sample-specific dependencies between text and images in mathematical problem-solving. This gives rise to two core issues: first, the supervisory signals for visual content are generalized and coarse-grained, lacking adaptation to the actual necessity of visual information in each sample; second, training feedback becomes inaccurate when visual rewards are uniformly applied without distinguishing the complementary relationships among inputs. These limitations hinder models from achieving precise multimodal reasoning. In this work, we propose a framework for modeling fine-grained visual dependencies in mathematical reasoning. We first construct the MathVis-Fine dataset, augmenting fine-grained visual annotations with visual dependency ratings. Building upon this dataset, we introduce a two-stage progressive visual enhancement training paradigm that balances answer correctness rewards and visual grounding rewards according to the intrinsic visual dependency level of each sample, thereby mitigating reward bias and improving supervision accuracy. Extensive experiments demonstrate that the MathVis-Fine framework effectively enhances visual perception progressively based on visual dependency, offering a more precise training framework for multimodal mathematical reasoning. We will release the dataset upon acceptance.
Wanshi Xu, Haokun Zhao, Haidong Yuan +2
School of ECE, Peking University · College of Computer Science and Artificial Intelligence, Fudan University · School of Software and Microelectronics, Peking University +1
Performing deliberate mathematical reasoning in visual contexts is a hallmark of advanced 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.
Mingze Yin, Xiaohan Wang, Dian Li +8
College of Computer Science and Technology, Zhejiang University · Tencent 3AI Thrust, HKUST (GZ) · Zhongguancun Academy +3