The GCN approach ensures that the sentence structure represented by the dependency tree is encoded efficiently, whereby the representations for nodes encode the local position of opinion words and the target words in the dependency tree.
the dependency tree G for any arbitrary sentence can be represented as an n × n adjacency matrix A, with entries A ij signaling if node i is connected to node j by a single dependency path in G. A ij = 1 if node i is connected to node j, and A ij = 0 otherwise.