# The web as a directed graph

## A graph

In mathematics, and more specifically in graph theory, a graph is a structure amounting to a set of objects in which some pairs of the objects are in some sense "related". The objects correspond to mathematical abstractions called vertices (also called nodes or points) and each of the related pairs of vertices is called an edge (also called an arc or line). Typically, a graph is depicted in diagrammatic form as a set of dots for the vertices, joined by lines or curves for the edges.^{[2]}

## A directed graph

In mathematics, and more specifically in graph theory, a directed graph (or digraph) is a graph that is a set of vertices connected by edges, where the edges have a direction associated with them.^{[3]}

## The web as directed graph

Each of the nodes represents a web site. Each edge represents a link either coming TO a website or leaving FROM a website.

In the case of our example above, node A links to node B. Node D also links to node B.

And another example of a directed graph

## Do you understand this?

## Standards

These standards are used from the IB Computer Science Subject Guide^{[4]}

- DescribeGive a detailed account or picture of a situation, event, pattern or process. how the web can be represented as a directed graph

## References

- ↑ http://www.flaticon.com/
- ↑ https://en.wikipedia.org/wiki/Graph_(discrete_mathematics)
- ↑ https://en.wikipedia.org/wiki/Directed_graph#Basic_terminology
- ↑ IB Diploma Programme Computer science guide (first examinations 2014). Cardiff, Wales, United Kingdom: International Baccalaureate Organization. January 2012.