where H(Y ) is the entropy term and XS are the subgraph's node features. In simpler terms, it finds a group of nodes in a graph that leads to the same prediction as utilising the information contained within the entire graph. The Explainer algorithm returns a node mask M which holds the importance of each node within G. The node mask can be plotted directly on the molecule for visual inference. To further ensure that the identified subgraph is a confident prediction by the Explainer, the subgraph fidelity curve can be calculated as follows: