Because
type: WorkPerformance
piano: http://data.carnegiehall.org/names/18187
soprano: http://data.carnegiehall.org/names/14322
performer: http://data.carnegiehall.org/names/14322
performer: http://data.carnegiehall.org/names/18187
work performed: http://data.carnegiehall.org/works/24098