Musical improvisation - Lycée Emmanuel d'Alzon (Nîmes)

This topic is about musical improvasition. We must determine how many different tunes are possible with notes and combinations giving. Knowing that we will start this improvisation with a C and that there isn't twice the same combinations with two notes in every tune so that's there isn't twice the same arrows (if we write C and D in this order, we can't get C and D twice but we can write D and C in this order). The drawing below that we can call a graph (a diagram with points called vertices: C, D, E, F, G, A and B, linked or not by segments called edges ) enable us to do know what are the possible combinations. Indeed, the arrows show us the correct combinations with the notes.