Weakness: 1. The writing needs a lot of improvement. Many of the concepts or notations are not explained. For example, what do “g_\alpha” and “vol(\alpha)” mean? What is an “encoding tree”(I believe it is not a common terminology)? Why can the encoding tree be used a tree kernel? Other than complexity, what is the theoretic advantage of using these encoding trees? 2. Structural optimization seems one of the main components and it has been emphasized several times. However, it seems the optimization algorithm is directly from some previous works. That is a little bit confusing and reduces the contribution. 3. From my understanding, the advantage over WL-kernel is mainly lower complexity, but compared to GIN or other GNNs, the complexity is higher. That is also not convincing enough. Of course, the performance is superior, so I do not see it as a major problem, but I would like to see more explanations of the motivation and advantages. 4. If we do not optimize the structural entropy but just use a random encoding tree, how does it perform? I think the authors need this ablation study to demonstrate the necessity of structural optimization.
2. Structural optimization seems one of the main components and it has been emphasized several times. However, it seems the optimization algorithm is directly from some previous works. That is a little bit confusing and reduces the contribution.