Hi Stephan, Should I make anything special in order to minimize my transducer? Mohri states in a paper that minimization of a WFST is a simply minimization of a FSA with the labels on the arcs of the WFST appropriately encoded. Is this encoding done internally in the fsa tool or should I do it separately as in the case with the AT&T fsm library? Or do you do it the other way: invert-determinize-invert? Best, Emilian