Let G = ( V , E ) {\displaystyle G=(V,E)} be a graph, where V {\displaystyle V} is the node set and E {\displaystyle E} is the edge set. Let N u {\displaystyle N_{u}} be the neighbourhood of some node u ∈ V {\displaystyle u\in V} . Additionally, let x u {\displaystyle \mathbf {x} _{u}} be the features of node u ∈ V {\displaystyle u\in V} , and e u v {\displaystyle \mathbf {e} _{uv}} be the features of edge ( u , v ) ∈ E {\displaystyle (u,v)\in E} .