Definition:Component of Graph

Definition
Let $G$ be a graph.

Let $H$ be a subgraph of $G$ such that:


 * $H$ is connected;


 * $H$ is not contained in any connected subgraph of $G$ which has more vertices or edges than $H$ has.

This graph has 4 components:


 * Components.png

If a graph has only one component, it is connected.