We note that while interactional synonymy relations in dialogue should be accounted for by semantic grammars or formal models of dialogue structure (such as DS-TTR (Eshghi et al., 2012), or KoS (Ginzburg, 2012)), lexical synonymy relations have to be learned from data.
for direct comparison, and for simplicity of exposition, we do the same here: we apply the method described for creating a user simulation (section 3.2.1), this time for the system side, resulting in a 'system simulation'.