Topics: Graph Theory
A graph is a mathematical structure that consists of two finite sets and .
- The elements of are called vertices or nodes.
- The elements of are called edges.
- The set of vertices must be a non-empty set, but the set of lines can empty.
We can use graphs to represent the relationship between different elements. A digraph is an example of a graph.
Graphs can be of several types (🗺).
Order and Cardinality
The order of is the cardinality of , while the size of is the cardinality of .
The following is a graph with vertices and edges :
We denote the minimum vertex degree in a graph with or , and the maximum with or .