An adjacency matrix A represents graph connectivity. For a graph G=(V,E), set Aij=1 when an edge connects nodes i and j, and 0 otherwise. For an undirected graph, A is symmetric: A=AT. section 11.4
Use the matrix to encode relational structure alongside node and edge information:
- Represent N nodes with an N×N adjacency matrix; directed edges need not produce a symmetric matrix. section 11.4
- Pair A with the node feature matrix X, whose N×F entries describe F features for each node. section 11.4
- Keep edge attributes separately in an M×S edge feature matrix E when M edges have S features each. section 11.4
- For PageRank, derive each page’s out-degree from adjacency entries and use it to construct link-following probabilities. section 7.1.1
CORA citation network
Treat each document as a node and each citation as a directed edge. The adjacency matrix records citation relationships, while a binary N×F feature matrix records whether dictionary words occur in each document. section 11.4







