Facts: The cattle dealer V and a prospective buyer K negotiate the sale of a cow with a sign with her name ’Resi’ hanging around her neck. V and K inspect the animal in the barn. Some time later, when they draw up a written deed of sale in V’s office, they enter the name ’Rosi’ to identify the animal. However, the animal inspected was ’Resi’. Rosi is at the other end of the barn, is the most valuable cow in the barn and should not be sold under any circumstances. V and K were wrong about the name. Nevertheless, K would now like ’Rosi’.

Question: Has a purchase contract been concluded? If so, about which animal?