Five ways to train agents dropped this week; two beat GRPO at the same GPU budget

RSIPO, DeltaTTG, TPPO, Ares and SALD all target sample efficiency. In preprints posted this week, the authors report gains over GRPO and PPO baselines without proportional compute increases.

Five preprints posted this week circle the same problem: training agents with reinforcement learning is expensive because the reward usually arrives only at the end. When a multi-turn agent finally succeeds or fails, the training signal says almost nothing about which of its fif…