Definition. Milestone process reward [ftip-00AD]
Definition. Milestone process reward [ftip-00AD]
For the source's fixed AIME problem, let
\[ M(y)=(m_1(y),\ldots ,m_5(y))\in \{0,1\}^5 \]record whether a completed response contains five declared milestones: a valid algebraic setup, correct root relations, correct integer bounds, a correct count for at least one branch, and correct subtraction of the overlap at the origin. With
\[ (w_1,\ldots ,w_5)=(0.05,0.05,0.10,0.15,0.25), \]the milestone process reward is
\[ r_{\rm proc}(y)=\sum _{i=1}^{5}w_i m_i(y). \]Appendix D.1 of Demystifying Reinforcement Learning Post-Training of Language Models[clay2026demystifying] gives Equation (6) and the milestone list above. In the experiment, a 32-billion-parameter instruction-tuned model classifies the completed trajectory. The displayed map is therefore richer than a deterministic final-answer verifier, even though it returns one scalar after the rollout.