Rewarding Efficient Reasoning Improves Abstention on Underspecified Tasks in Reasoning Models

arXiv:2609.20846 · cs.CL, cs.LG · Submitted 2026-08-05 · Read on arXiv

cs.CL, cs.LG

Submitted: 2026-08-05

Updated: 2026-08-05

Comments: 19 pages, 9 figures

License: http://arxiv.org/licenses/nonexclusive-distrib/1.0/

Terminology

• Abstention — 2× in this paper · explained in 1 episode
• Fine-Tuning — 1× in this paper · explained in 5 episodes
• GRPO — 1× in this paper · explained in 6 episodes

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