When a graph is sparse, information between distant nodes may take many message-passing rounds to travel. A virtual edge adds an artificial connection between otherwise unconnected nodes, creating a long-range route for messages without treating it as a true physical edge. section 7.3.2
A shortcut between atoms
In a molecule, two atoms that are not bonded can still exchange messages through a specialized virtual channel. Like hallways between distant rooms, these connections provide shortcuts across nodes; residual connections instead provide shortcuts across network layers. The model can learn whether to use or ignore virtual edges. section 7.3.2
