Before revision:  Prior work has attempted to quantify the number of facts PLMs learn, but we present, using synthetic data, the first study that establishes a causal relation between facts present in training and facts learned by the PLM.
After revision:  Prior work has attempted to quantify the number of facts PLMs learn, but we present, using synthetic data, the first study that investigates the causal relation between facts present in training and facts learned by the PLM.