Bounded Counter Languages
arXiv:1204.0833 · doi:10.1007/978-3-642-31623-4_21
Abstract
We show that deterministic finite automata equipped with two-way heads are equivalent to deterministic machines with a single two-way input head and linearly bounded counters if the accepted language is strictly bounded, i.e., a subset of for a fixed sequence of symbols . Then we investigate linear speed-up for counter machines. Lower and upper time bounds for concrete recognition problems are shown, implying that in general linear speed-up does not hold for counter machines. For bounded languages we develop a technique for speeding up computations by any constant factor at the expense of adding a fixed number of counters.