{
  "id": 6382929,
  "title": "ThinkPrior: Zero-Rollout Difficulty Priors for Cold-Start Prompt Selection in RLVR",
  "url": "https://urgent.news/2026/09/08/thinkprior-zero-rollout-difficulty-priors-for-cold-start-prompt",
  "topic": "ai",
  "section": "AI",
  "published": "2026-09-08T17:30:12.000Z",
  "source": {
    "name": "arXiv cs.AI",
    "slug": "arxiv-cs-ai",
    "url": "https://arxiv.org/abs/2609.09075v1"
  },
  "original_language": "en",
  "account": null,
  "summary": "In reinforcement learning with verifiable rewards (RLVR) trained with group relative policy optimization (GRPO), the KL-free reward-advantage term studied here depends on within-group reward variation. If all rollouts in a group are correct or all are wrong, their group-relative advantages are identically zero; these zero-advantage silent groups provide no reward-advantage gradient, yet uniform…",
  "key_points": [],
  "editors_take": null,
  "illustration": null,
  "coverage": {
    "outlets": 1,
    "also_reported_by": []
  },
  "ai_generated": true,
  "disclaimer": "Summaries, key points and the editor’s take are written by software from other outlets’ reporting and may contain errors — always check the linked original."
}