A Simple Method for Building Bimachines from Functional Finite-State Transducers.

The standard construction of a bimachine from a functional transducer involves a preparation step for converting the transducer into an unambiguous transducer (A transducer is unambiguous if there exists at most one successful path for each label.). The conversion involves a specialized determinization. We introduce a new construction principle where the transducer is directly translated into a bimachine. For any input word accepted by the transducer the bimachine exactly imitates one successful path of the transducer. For some classes of transducers the new construction can build a bimachine with an exponentially lower number of states compared to the standard construction. We first present a simple and generic variant of the construction. A second specialized version leads to better complexity bounds in terms of the size of the bimachine.