On languages specified by relative acceptance

Algebraic caractérisations of NTIME$(F)$ and NTIME$(F, A)$

“…Whereas in [2,3,5 ], each characterisation is proven as a single result, most of these characterisations are obtained in this paper as special cases of the characterisations of two families of classes of formai languages.…”

“…Starting with the 'Représentation Lemma' presented by R. V. Book and C. Wrathall in [5], a (uniform) représentation for the languages of NTIME(is,4) is established in Lemma 2.1. Theorem 2 characterizes the class NTIME (F, A) algebraically.…”

“…In recent years, many classes of formai Ianguages have been algebraically characterized [2,3,5 ]. Generally, these characterisations were obtained by use of the regular Ianguages or other classes of Ianguages, e. g. the class of linear-context-free Ianguages as a basis and allowing closure under elementary 366 H.-J.…”

“…So many characterisations proven or stated in [2,3,5 ] are obtained as special cases of two gênerai characterisations. Furthermore, two uniform représentations for the languages of the two families of classes of languages are provided by the proofs of the theorems.…”

“…So as to get a basic représentation for the languages of NTIME(F, A) in section 2, a modified version of the 'Représentation Lemma' by R. V. Book and C. Wrathall in [5] serves as a starting-point for the characterisation of NTIME(F, A). At the end of each section, several well known classes of CHARACTERISATIONS OF NTIME(F) AND ISTHME^, A) 367 formai languages are described as an application of the gênerai results: in section 1 the class RE of r.e.…”