The idea of using p-adic numbers in Turing machines and finite automata to describe random branching of the process of computation was recently introduced. In the last two years some advantages of ultrametric algorithms for finite automata and Turing machines were explored. In this paper advantages of ultrametric automata with one head versus multihead deterministic and nondeterministic automat...

Network intrusion detection systems (NIDS) make extensive use of regular expressions as attack signatures. Internally, NIDS represent and operate these signatures using finite automata. Existing representations of finite automata present a well-known time-space tradeoff: Deterministic automata (DFAs) provide fast matching but are memory intensive, while non-deterministic automata (NFAs) are spa...

It was proved earlier by A. Ambainis and R. Freivalds that the quantum finite automata with pure states can have exponentially smaller number of states than the deterministic finite automata recognizing the same language. There is a never published “folk theorem” claiming that the quantum finite automata with mixed states are no more than super-exponentially concise than the deterministic finit...

one-way quantum finite automata are reversible in nature, which greatly reduces its accepting property. In fact, the set of languages accepted by one-way quantum finite automata is a proper subset of regular languages. In this paper, we replace the tape head of one-way quantum finite automata with DNA double strand and name the model Watson-Crick quantum finite automata. The noninjective comple...

We show that the regularity and equivalence problems are decidable for deterministic weak pushdown ω-automata, giving a partial answer to a question raised by Cohen and Gold in 1978. We prove the decidability by a reduction to the corresponding problems for deterministic pushdown automata on finite words. Furthermore, we consider the problem of deciding for pushdown games whether a winning stra...