{"slug": "s3ac-stabilized-selective-and-scalable-actor-critic-for-llm-reasoning", "title": "S3AC: Stabilized, Selective, and Scalable Actor-Critic for LLM Reasoning", "summary": "Researchers present S3AC (Stabilized, Selective, and Scalable Actor-Critic), an actor-critic method for reinforcement learning with verifiable rewards (RLVR) on long chain-of-thought reasoning that the authors say addresses the lack of token-level credit assignment in critic-free methods, which typically rely on grouped rollouts to estimate prompt-level signals. The work targets the costly critic training that critic-free approaches avoid, aiming to combine token-level credit assignment with stable, selective and scalable training for LLM reasoning.", "body_md": "Critic-free methods are widely used in reinforcement learning with verifiable rewards (RLVR) for long chain-of-thought (CoT) reasoning, avoiding difficult and costly critic training. Common alternatives lack token-level credit assignment and typically rely on grouped rollouts to estimate prompt-spec", "url": "https://wpnews.pro/news/s3ac-stabilized-selective-and-scalable-actor-critic-for-llm-reasoning", "canonical_source": "https://aiflash.com/news/140269/", "published_at": "2026-10-27 06:00:23+00:00", "updated_at": "2026-10-27 06:13:03.571288+00:00", "lang": "en", "topics": ["machine-learning", "large-language-models", "ai-research", "artificial-intelligence"], "entities": ["S3AC"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/s3ac-stabilized-selective-and-scalable-actor-critic-for-llm-reasoning", "markdown": "https://wpnews.pro/news/s3ac-stabilized-selective-and-scalable-actor-critic-for-llm-reasoning.md", "text": "https://wpnews.pro/news/s3ac-stabilized-selective-and-scalable-actor-critic-for-llm-reasoning.txt", "jsonld": "https://wpnews.pro/news/s3ac-stabilized-selective-and-scalable-actor-critic-for-llm-reasoning.jsonld"}}