Nondeterministic multicounter machines and complementation

On Stateless Multicounter Machines

We investigate the computing power of stateless multicounter machines with reversal-bounded counters. Such a machine has m-counters and it operates on a one-way input delimited by left and right end markers. The move of the machine depends only on the symbol under the input head and the signs of the counters (zero or positive). At each step, every counter can be incremented by 1, decremented by...

Hierarchies and Characterizations of Stateless Multicounter Machines

We investigate the computing power of stateless multicounter machines with reversal-bounded counters. Such a machine can be deterministic, nondeterministic, realtime (the input head moves right at every step), or non-realtime. The deterministic realtime stateless multicounter machines has been studied elsewhere [1]. Here we investigate non-realtime machines in both deterministic and nondetermin...

Learning Nondeterministic Mealy Machines

In applications where abstract models of reactive systems are to be inferred, one important challenge is that the behavior of such systems can be inherently nondeterministic. To cope with this challenge, we developed an algorithm to infer nondeterministic computation models in the form of Mealy machines. We introduce our approach and provide extensive experimental results to assess its potentia...

Nondeterministic Space Is Closed under Complementation

Nondeterministic space is closed under complementation

In this paper we show that nondeterministic space s n is closed under com plementation for s n greater than or equal to log n It immediately follows that the context sensitive languages are closed under complementation thus settling a question raised by Kuroda in See Hartmanis and Hunt for a discussion of the history and importance of this problem and Hopcroft and Ullman for all relevant backgr...