GRAPHS

Consists of a set of nodes or point some of which are connected by edges or lines.

A (hypothetical) graph of nonstop airline flights.

Molecule alcohol:

Def. A graph G=(V,E) which V is the set of nodes,

and E is the set of edges,

note:.

1. each edge is a set of pair of vertexes. No order implied.
2. , i could be equal to j.
   self-loop
   

   

3. One also allows multiple edge between two node in a general graph
   

   

4. Cardinality of V, |V|=n, number of nodes, |E|=m, number of edges.