#### Edge list An array of pairs of vertex numbers. A third number can be added to represent weighted edges. ``` [ [0,1], [0,6], [0,8], [1,4], [1,6], [1,9], [2,4], [2,6], [3,4] ] ``` #### Adjacency list For each vertex i, store an array of the vertices adjacent to it.  #### Adjacency map Similar to an adjacency list except the list of neighbors is stored in a hash table instead of an array. This has much better performance than an adjacency list. #### Adjacency matrix Two dimensional array that tells you whether an edge between vertexes. This isn't the most space efficient. So adjacency lists & adjacency maps are more practical in the real world.