  This paper defines a subregular class of functions called the tier-based
synchronized strictly local (TSSL) functions. These functions are similar to
the the tier-based input-output strictly local (TIOSL) functions, except that
the locality condition is enforced not on the input and output streams, but on
the computation history of the minimal subsequential finite-state transducer.
We show that TSSL functions naturally describe rhythmic syncope while TIOSL
functions cannot, and we argue that TSSL functions provide a more restricted
characterization of rhythmic syncope than existing treatments within Optimality
Theory.
