A Appendix

We conduct experiments on four benchmark graph datasets, including Cora, Pubmed, Coauthor-Physics and Ogbn-arxiv. They are widely used to study the over-smoothing issue and test the performance of deep GNNs. We use the public train/validation/test split in Cora and Pubmed, and randomly split Coauthor-Physics by following the previous practice. They are summarized as follows: GCN [15]. It is mathematically defined in Eq. Approximate personalized propagation of neural predictions (APPNP) [50].