Definition:Graph (Graph Theory)/Informal Definition

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Informal Definition

A graph is intuitively defined as a pair consisting of a set of vertices and a set of edges.

ExampleOfGraph.png


Vertex

Let $G = \left({V, E}\right)$ be a graph.

The vertices (singular: vertex) are the elements of $V$.

Informally, the vertices are the points that are connected by the edges.


In the above, the vertices (singular: vertex) are the points $A, B, C, D, E, F, G$ which are marked as dots.


Edge

Let $G = \struct {V, E}$ be a graph.

The edges are the elements of $E$.


In the above, the edges are $AB, AE, BE, CD, CE, CF, DE, DF, FG$.