Local Coherence or Global Validity? Investigating RLVR Traces in Math Domains

Fuente: arXiv
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Auteurs principaux: Samineni, Soumya Rani, Kalwar, Durgesh, Gangal, Vardaan, Bhambri, Siddhant, Kambhampati, Subbarao
Format: Preprint
Publié: 2025
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author Samineni, Soumya Rani
Kalwar, Durgesh
Gangal, Vardaan
Bhambri, Siddhant
Kambhampati, Subbarao
author_facet Samineni, Soumya Rani
Kalwar, Durgesh
Gangal, Vardaan
Bhambri, Siddhant
Kambhampati, Subbarao
contents Reinforcement Learning with Verifiable Rewards (RLVR)-based post-training of Large Language Models (LLMs) has been shown to improve accuracy on reasoning tasks and continues to attract significant attention. Existing RLVR methods, however, typically treat all tokens uniformly without accounting for token-level advantages. These methods primarily evaluate performance based on final answer correctness or Pass@K accuracy, and yet make claims about RL post-training leading to improved reasoning traces. This motivates our investigation into the effect of RL post-training on intermediate tokens which are not directly incentivized. To study this, we design an experimental setup using the GRPO algorithm with Qwen-2.5-0.5B model on the GSM8K dataset. We introduce trace coherence, a First-Order Logic (FOL)-based measure to capture the consistency of reasoning steps by identifying errors in the traces. We distinguish between trace validity and trace coherence, noting that the former implies logical soundness while the latter measures local coherence via lack of errors. Our results show that RL post-training overall improves trace coherence with the most significant gains on problems where the base model fails but the RL model succeeds. Surprisingly, RL enhances local coherence without necessarily producing valid or correct solutions. This highlights a crucial distinction: improved local coherence in reasoning steps does not guarantee final answer correctness. We argue that claims of improved reasoning via RL must be examined with care, as these may be based on improved trace coherence, which may not translate into fully valid mathematical proofs.
format Preprint
id arxiv_https___arxiv_org_abs_2510_18176
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Local Coherence or Global Validity? Investigating RLVR Traces in Math Domains
Samineni, Soumya Rani
Kalwar, Durgesh
Gangal, Vardaan
Bhambri, Siddhant
Kambhampati, Subbarao
Artificial Intelligence
Machine Learning
Reinforcement Learning with Verifiable Rewards (RLVR)-based post-training of Large Language Models (LLMs) has been shown to improve accuracy on reasoning tasks and continues to attract significant attention. Existing RLVR methods, however, typically treat all tokens uniformly without accounting for token-level advantages. These methods primarily evaluate performance based on final answer correctness or Pass@K accuracy, and yet make claims about RL post-training leading to improved reasoning traces. This motivates our investigation into the effect of RL post-training on intermediate tokens which are not directly incentivized. To study this, we design an experimental setup using the GRPO algorithm with Qwen-2.5-0.5B model on the GSM8K dataset. We introduce trace coherence, a First-Order Logic (FOL)-based measure to capture the consistency of reasoning steps by identifying errors in the traces. We distinguish between trace validity and trace coherence, noting that the former implies logical soundness while the latter measures local coherence via lack of errors. Our results show that RL post-training overall improves trace coherence with the most significant gains on problems where the base model fails but the RL model succeeds. Surprisingly, RL enhances local coherence without necessarily producing valid or correct solutions. This highlights a crucial distinction: improved local coherence in reasoning steps does not guarantee final answer correctness. We argue that claims of improved reasoning via RL must be examined with care, as these may be based on improved trace coherence, which may not translate into fully valid mathematical proofs.
title Local Coherence or Global Validity? Investigating RLVR Traces in Math Domains
topic Artificial Intelligence
Machine Learning
url https://arxiv.org/abs/2510.18176