Issue No. 09 - September (1974 vol. 23)
T. Ibaraki , Department of Applied Mathematics and Physics, Faculty of Engineering, Kyoto University
The above paper1 by Mag? discusses the state assignment problem by means of monotone increasing (i.e., positive) next-state functions for both synchronous and asynchronous sequential networks. It may be interesting to note that the same subject for synchronous sequential networks has also been studied under a somewhat different title: "Fail-Safe Realization of Sequential Machines." This is because a realization with positive next-state functions (and positive output functions) results in a fail-safe sequential circuit in a certain sense.
T. Ibaraki, "Comments on "Monotone Functions in Sequential Circuits"", IEEE Transactions on Computers, vol. 23, no. , pp. 989-990, September 1974, doi:10.1109/T-C.1974.224072