A work prepared by two or more authors with the intention that each contribution will merge into one inseparable whole. If one songwriter writes all of the music to a joint work and another songwriter writes all of the lyrics to the joint work, each songwriter will own 50% of both the music and lyrics.

Practicing And Performing Music
There is a perception that performing and practicing music are two very different activities. I think that the relationship between performing and practicing is deeply intertwined and at a certain level the distinction between the two virtually disappears.