Graphs with networkx
Python networkx library
A simple undirected graph (or simply, a graph) G is defined as G=(V,E) , where
V={v1, .., vn} is a set of nodes (also called vertices) and E={{vk,vw} .., {vi,vj}} is a set
of two-sets (set of two elements) of edges.
The order of a graph is the number of its vertices |V|.
The size of a graph is the number of its edges |E|.
The degree of a vertex is the number of edges that are adjacent to it