Research repositories

This paper reframes practical token-level on-policy distillation as a temporally truncated approximation to sequence-level reverse-KL optimization. It introduces γOPD, which discounts future token log-ratios to trade long-range credit assignment against variance, and reward-compatible bounded mixing, which combines bounded teacher-derived credit with binary verifier rewards. Across mathematical reasoning, code generation, same-size, smaller-student, and multi-teacher settings, the paper reports generally stronger aggregate performance than compared OPD methods. Ablations attribute gains to complementary temporal discounting and bounded reward mixing, while training analyses report steadier optimization and negligible additional overhead. Experiments are confined to models below 10B parameters.