  Matching Dependencies (MDs) are a relatively recent proposal for declarative
entity resolution. They are rules that specify, given the similarities
satisfied by values in a database, what values should be considered duplicates,
and have to be matched. On the basis of a chase-like procedure for MD
enforcement, we can obtain clean (duplicate-free) instances; actually possibly
several of them. The resolved answers to queries are those that are invariant
under the resulting class of resolved instances. In previous work we identified
some tractable cases (i.e. for certain classes of queries and MDs) of resolved
query answering. In this paper we further investigate the complexity of this
problem, identifying some intractable cases. For a special case we obtain a
dichotomy complexity result.
