pith:URSNDDDQ
Beyond GRPO and On-Policy Distillation: An Empirical Sparse-to-Dense Reward Principle for Language-Model Post-Training
A four-stage workflow with sparse-reward RL on a teacher followed by on-policy distillation outperforms direct GRPO on LLM math reasoning.
arxiv:2605.12483 v3 · 2026-05-12 · cs.LG · cs.AI
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Claims
On verifiable math with a Qwen3-1.7B deployment student, the workflow reaches 79.3% MATH and 25.2% AIME 2024 (avg@16), versus 75.9% and 19.8% for direct GRPO on the same student.
The teacher model must itself be reward-shaped (condition C1) and lie within a small KL divergence of the student (condition C2) for the on-policy distillation stage to provide informative dense implicit rewards.
A four-stage sparse-to-dense reward workflow for LLM post-training reaches 79.3% on MATH and 25.2% on AIME 2024 with a 1.7B student, outperforming direct GRPO by enforcing dense implicit rewards from a shaped teacher.
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| First computed | 2026-05-20T00:01:44.012985Z |
|---|---|
| Builder | pith-number-builder-2026-05-17-v1 |
| Signature | Pith Ed25519
(pith-v1-2026-05) · public key |
| Schema | pith-number/v1.0 |
Canonical hash
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curl -sH 'Accept: application/ld+json' https://pith.science/pith/URSNDDDQZODJVNCAIOQO6TBQP7 \
| jq -c '.canonical_record' \
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Canonical record JSON
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