  The idea that discourse relations are construed through explicit content and
shared, or implicit, knowledge between producer and interpreter is ubiquitous
in discourse research and linguistics. However, the actual contribution of the
lexical semantics of arguments is unclear. We propose a computational approach
to the analysis of contrast and concession relations in the PDTB corpus. Our
work sheds light on the extent to which lexical semantics contributes to
signaling explicit and implicit discourse relations and clarifies the
contribution of different parts of speech in both. This study contributes to
bridging the gap between corpus linguistics and computational linguistics by
proposing transparent and explainable models of discourse relations based on
the synonymy and antonymy of their arguments.
