So what is interesting here is that they managed to set up the reward model in such a simple and cost-effective way that CoT emerges as the most optimal strateg

So what is interesting here is that they managed to set up the reward model in such a simple and cost-effective way that CoT emerges as the most optimal strategy for solving math problems, without explicitly fine-tuning the model to do so. This naturally raises the question: How do you design a reward model to elicit the desired emergent behavior in a system?