Week 1 Flashcards

1
Q

When is a network undirected?

A

If gij = gji, the matrix is also symmetric.

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2
Q

What is the notation of a node and a relationship?

A
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3
Q

What is the definition of the Neighborhood? What is the definition of the degree?

A
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4
Q

What is a walk?

A
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5
Q

What is a path?

A
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6
Q

What is a cycle?

A
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7
Q

What is a geodesic?

A
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8
Q

What is the diameter?

A
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9
Q

When is a network connected?

A

If there is a path between every two nodes

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10
Q

What is the definition of a maximal connected subgraph?

A

(see image). A maximal connected subgraph is just a part of the graph where every node is connected to each other.

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11
Q

What is the degree distribution?

A

P(d), it tells the percentage of nodes that has d number of connections.

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12
Q

What are some examples of degree distributions?

A
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13
Q

What is the difference between a Poisson and Scale-Free degree distribution?

A
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14
Q

Which is the scale-free distribution?

A
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15
Q

What is homophily?

A

The bias towards similar individuals.

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16
Q

What is a clique? What is clustering?

A
17
Q

How to measure cliquishness/clustering?

A

Usually this is measured by measuring triplets. (see image)

You can also use overall clustering = 3 * all closed triangles / number of connected triplets

18
Q

What are the 4 main categories for centrality?

A
19
Q

How to compute degree centrality?

A

di(g)/(n-1)

Note: this misses information about location

20
Q

How to compute closeness centrality?

A

(n - 1)/Σjl(i, j)

Note: l(i, j) number of steps in the shortest path from node i to j

21
Q

How to compute decay centrality?

A

(see image)

We can also normalize this decay centrality by dividing by ((n-1)𝛅), since it is the lowest degree possible.

22
Q

How to compute betweenness centrality?

A
23
Q

How to compute the eigenvalue based centrality?

A

Note: this is a self-referential concept.