A method prepares a functional finite-state transducer (FST) with an
epsilon or empty string on the input side for factorization into a
bimachine. The method creates a left-deterministic input finite-state
automation (FSA) by extracting and left-determinizing the input side of
the functional FST. Subsequently, the corresponding sub-paths in the FST
are identified for each arc in the left-deterministic FST and aligned.