Degree

number of edges connected to a node. Average degree = 2*edges/nodes

Path

how many edges between two specific nodes.

Clustering coefficent

How many percentage of the triple nodes connected together.

In a team, we can use the above to represent a team. 

How to form a network?

(1) Random connection

P: the probability of 2 nodes connected

N:NO of the nodes.

if P> 1/(N-1) then the whole network may conncet.

(2) Small world

(3)Preferential attachment

Nodes may connect to a node with the probability proportional to the NO of the nodes connecting to this node. Just handful of nodes have high degree.