In the same way that the same person relates in different ways depending on who is in front of them, the same element that relates within different sets, takes on a different meaning in each case.

• Collections are sets of elements of the same type, which do not have a specific order (horizontal or vertical) of their elements, so all orders are possible. We represent them with the element abbreviation and their numerical values in square brackets [ ].

Example of collection: N [0 4 7]

Scales, chords or triads are examples of collections, frequently used in music.

• Successions are sets of elements of the same type, which already have the order of their elements specified. We represent them with the abbreviation of the element and their numerical values in parentheses ( ).

Example of succession: N (3 5 4 4 8 3 6 4)

Rhythmic patterns and rhythmic cells are examples of successions frequently used in music.

From a sequence, we can also extract the collection of elements used, which we usually order in ascending order.

Example: from the sequence N (3 5 4 8 3 6 4), we extract the collection N [3 4 5 6 8] [3 4 5 6 8]

Example of succession: N (4 7 7 0 4)

Example of succession: iT (3 3 4 4 2 4)

• The set of sets: when we give the element function to the sets of basic elements, we are generating new elements which we will call complex elements. With these new complex elements we can create a set of sets.

For example, in a succession of triads, the complex elements are the triads, since each one is a set of 3 Notes by itself.