Given an input sentence, we employ BERT (Devlin et al., 2019) as our sentence encoder by extracting the final hidden state of the [CLS] token as the representation, where [CLS] is the special classification embedding in BERT.
given a claim c and N pieces of retrieved evidence {e 1 , e 2 , ..., e N }, we feed each evidence-claim pair (e i , c) into BERT to obtain the evidence representation e i .