Here, we follow the brief description of GNNs from . A graph G is represented by a tuple G = (V, E), where V is the set of nodes (or vertices) and E ⊆ V ×V is the set of edges. Here, we assume that the nodes are associated with feature vectors x u of dimension d for all u ∈ V. The graph structure is represented by A, the adjacency matrix of a graph G such that A uv = 1 if (u, v) ∈ E and A uv = 0 otherwise. For a node u ∈ V the set of neighbouring nodes is denoted by