Reviews: On the number of variables to use in principal component regression

In the paper, the authors discussed PCR, a well-know variant of regression models, and showed the existence of a "double descent" phenomenon. The paper is technically sound and relatively well-written. I check most of the math and they are correct and reasonable to follow. I do have some concern that too much of the space is taken by the algebra which could make it difficult for readers to grasp the high-level intuition, specifically if they do not have enough time to plough through the equations. Considering the space limit for a NeurIPS submission, I think it's better to reorganize some of the proofs to the appendix, and add a discussion/conclusion session to highlight more about the intuitions.