**Graph: A** set of interconnected dots

**Summits (vertices, a verte**x): The dots of a graph are called adjacent s**ummitsSommets (adjacent vertices): **Two peaks are adjacent if they are connected to each o**ther, Edge: Th**e link between two peaks is called an edge if the relationship between two summit is not oriented (no notion of precedence, or order in which one visits the two summits).

**Arc (arc**): The oriented link between two summits (it is an arrow that indicates the meaning of the oriented relationship, there is a notion of execution order **and constraint to visit the two peaks)**The degree of a vertex: Number of** edges that are start from a su**mmit. Order of a graph: The n**umber of tops in a graph. Re**lated graph :: A graph is related if all the tops are connected b**y any chain. Eulerian path: A** chain that takes all the edges once from the graph.

**Adjacent Matrix: **The adjacence matrix of a graph is a matrix whose lines and columns are both indexed by the tops of the graph, with a 1 in the cell for row i and column j when the tops i and j are adjacent , and a 0 if not.