Before revision:  Novikova et al., 2017), we show that an additional problem arises when applied for AMR-to-text evaluation because mapping from the more abstract domain of AMR to the more concrete domain of sentences allows for manifold sentence realizations.
After revision:  Novikova et al., 2017), we show that an additional problem arises when applied for AMR-to-text evaluation , since an abstract meaning representation allows for numerous surface realizations.