The computations of programs are driven by their inputs. The outputs are just the results of the computations, and they have no influence on the course that the computations take. Consequently, it seems that much can be studied about finitestate transducers, or equivalently, about finitememory programs even when their outputs are ignored. The advantage of conducting a study of such strippeddown finitestate transducers is in the simplified argumentation that they allow.

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