For each of the components, we can derive an appropriate loss function: the (entity) alignment loss al , the (path label) prediction loss pr , the (subject-path) verification loss ve , and the (object) answering loss an .
it is worth noting that to properly define the verification loss ve , we need to introduce "negative examples" for CLS.To that end, denote D qsr is the set of all training examples for path label prediction (ENC-DEC).