Conceptos Básicos
Redundancy in the information flow and computation of graph neural networks can lead to oversquashing, limiting their expressivity and accuracy. The proposed DAG-MLP approach systematically eliminates redundant information by using neighborhood trees and exploits computational redundancy through merging of isomorphic subtrees, achieving higher expressivity and accuracy compared to standard graph neural networks.
Resumen
The content discusses the problem of redundancy in graph neural networks (GNNs) and proposes a novel approach called DAG-MLP to address it.
Key highlights:
- Redundancy in the information flow and computation of GNNs can lead to the issue of oversquashing, where the growing neighborhood of a node cannot be accurately represented by a fixed-sized embedding.
- The authors develop a neural tree canonization technique and apply it to unfolding trees and k-redundant neighborhood trees (k-NTs) to eliminate redundant information.
- To exploit computational redundancy, the authors merge multiple trees representing node neighborhoods into a single directed acyclic graph (DAG), identifying isomorphic subtrees.
- The DAG-MLP architecture recovers the computational graph of standard GNNs for unfolding trees, while avoiding redundant computations in the presence of symmetries.
- Theoretical analysis shows that the expressivity of k-NTs and unfolding trees is incomparable, and k-NTs can mitigate oversquashing more effectively.
- Experiments on synthetic and real-world datasets demonstrate that DAG-MLP with k-NTs outperforms standard GNNs and other related methods, especially on tasks with heterophily.