Oliver plays violin in the concert.
If people play the instrument in the concert, then he is good at playing this kind of instrument. Peter plays piano, violin, and saxophone. Peter was invited to play piano at the concert hall. Oliver and Peter were both invited to perform in the concert. Oliver plays a different musical instrument from Peter in the concert.
∀y (∀x (PlayInConcert(y, x) → GoodAt(y, x))) Play(peter, piano) ∧Play(peter, violin) PlayInConcert(peter, piano) PlayerInConcert(peter) ∧ PlayerInConcert(oliver) ¬PlayInConcert(oliver, piano)