1. Typology of detection methods and quality criteria

1.1 Definitions and typology

Community detection involves grouping together a set of individuals or objects according to various criteria or constraints. The term community detection tends to be applied to individuals engaged in social relationships. From a mathematical point of view, we'll see later that individuals can be represented by vertices of a graph (also known as graph nodes) and the relationships that unite them by graph links, also known as graph arcs. Since many networks other than social networks can be modeled by graphs, it's easy to see how community detection techniques can be extended to many other fields, such as neural networks or protein interactions.

There are two main types of groupings to consider:

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