The extraction of relations between entities has been a long-standing topic of research, with work spanning more than a couple of decades, e.g., ACE (Doddington et al., 2004) and MUC (Grishman and Sundheim, 1996).
sentence-level Relation Extraction (RE) has been typically modeled with supervised approaches, using manually annotated data, such as ACE (Kambhatla, 2004).