Synchronous Models of Language
  In synchronous rewriting, the productions of two rewriting systems are paired and applied synchronously in the derivation of a pair of strings. We present a new synchronous rewriting system and argue that it can handle certain phenomena that are not covered by existing synchronous systems. We also prove some interesting formal/computational properties of our system. 
Owen Rambow (CoGenTex, Inc) and Giorgio Satta (Padova)