Week 1 Flashcards
When is a network undirected?
If gij = gji, the matrix is also symmetric.
What is the notation of a node and a relationship?
What is the definition of the Neighborhood? What is the definition of the degree?
What is a walk?
What is a path?
What is a cycle?
What is a geodesic?
What is the diameter?
When is a network connected?
If there is a path between every two nodes
What is the definition of a maximal connected subgraph?
(see image). A maximal connected subgraph is just a part of the graph where every node is connected to each other.
What is the degree distribution?
P(d), it tells the percentage of nodes that has d number of connections.
What are some examples of degree distributions?
What is the difference between a Poisson and Scale-Free degree distribution?
Which is the scale-free distribution?
What is homophily?
The bias towards similar individuals.
What is a clique? What is clustering?
How to measure cliquishness/clustering?
Usually this is measured by measuring triplets. (see image)
You can also use overall clustering = 3 * all closed triangles / number of connected triplets
What are the 4 main categories for centrality?
How to compute degree centrality?
di(g)/(n-1)
Note: this misses information about location
How to compute closeness centrality?
(n - 1)/Σjl(i, j)
Note: l(i, j) number of steps in the shortest path from node i to j
How to compute decay centrality?
(see image)
We can also normalize this decay centrality by dividing by ((n-1)𝛅), since it is the lowest degree possible.
How to compute betweenness centrality?
How to compute the eigenvalue based centrality?
Note: this is a self-referential concept.
