Because
type: WorkPerformance
piano: http://data.carnegiehall.org/names/10180
unspecified voice: http://data.carnegiehall.org/names/33898
performer: http://data.carnegiehall.org/names/10180
performer: http://data.carnegiehall.org/names/33898
work performed: http://data.carnegiehall.org/works/24098