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## Summary/Background

A graph is a set of points, called vertices or nodes, connected by lines called edges or arcs. A simple graph is one that has no loops and in which no pair of vertices are connected by more than one edge. The number of edges incident on a vertex is called its order, degree or valency. This page uses Macromedia Flash. Your browser will need to have the Flash plugin installed - freely available from Macromedia. Flash movies designed by Helen Foster, Alton College, UK, and used with her permission.

## Glossary

### connected

of two vertices if there is a path between them.

### degree

On a graph: the number of edges incident to a vertex.
In geometry: a measure of angle

### edge

the line connecting two vertices of a graph, also known as arc or line.

### graph

A diagram showing a relationship between two variables.
The diagram shows a vertical y axis and a horizontal x axis.

### valency

The number of edges incident to a vertex.

### vertex

A point or node of a graph.

Full Glossary List

## This question appears in the following syllabi:

SyllabusModuleSectionTopicExam Year
AQA AS Further Maths 2017Discrete MathsNetworksPlanarity-
AQA AS/A2 Further Maths 2017Discrete MathsNetworksPlanarity-
Edexcel A-Level (UK - Pre-2017)D1Algorithms on graphsPlanarity-
Edexcel AS Further Maths 2017Decision Maths 1Algorithms on GraphsPlanarity-
Edexcel AS/A2 Further Maths 2017Decision Maths 1Algorithms on GraphsPlanarity-
I.B. Higher Level10Algorithms on graphsPlanarity-
OCR A-Level (UK - Pre-2017)D1Algorithms on graphsPlanarity-
OCR AS Further Maths 2017Discrete MathsNetwork AlgorithmsPlanarity-
OCR MEI AS Further Maths 2017Modelling with AlgorithmsNetworksPlanarity-
OCR-MEI A-Level (UK - Pre-2017)D1Algorithms on graphsPlanarity-
Universal (all site questions)AAlgorithms on graphsPlanarity-