In mathematics, a graph is a structure that represents a set of objects in which some pairs of the objects are 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 link or line) . Graphs are one of the objects of study in discrete mathematics and the basic subject studied by graph theory.
In general, a graph can be defined as a pictorial representation or a diagram that represents data or values in an organized manner. The points on the graph often represent the data, and the types of graphs include pictographs, bar graphs, and line graphs. Pictographs are graphs that show pictures, and each picture represents a certain number of items. Bar graphs represent numerical data by rectangles (or bars) of equal width and varying height, and the height or length of each bar relates directly to its value. Line graphs use dots connected by lines to show the relationship between two sets of data.
Graphs can be used to represent accrued data, which can be either quantitative or qualitative data. They are also important in computer science, where they are used to represent relationships between objects.
