  We introduce the notion of multi-pattern, a combinatorial abstraction of
polyphonic musical phrases. The interest of this approach lies in the fact that
this offers a way to compose two multi-patterns in order to produce a longer
one. This dives musical phrases into an algebraic context since the set of
multi-patterns has the structure of an operad; operads being structures
offering a formalization of the notion of operators and their compositions.
Seeing musical phrases as operators allows us to perform computations on
phrases and admits applications in generative music: given a set of short
patterns, we propose various algorithms to randomly generate a new and longer
phrase inspired by the inputted patterns.
