Showing papers by "Kamala Krithivasan published in 1993"
Proceedings Article•
01 Jan 1993TL;DR: It is shown that this form of nondeterminism corresponds to the traditional notion in the unbounded-time case, but there appear to he differences when real.time or linear cellular automata are considered.
Abstract: A new mechanism for introducing nondeterminism on the cellular automaton model is introduced. It is shown that this form of nondeterminism corresponds to the traditional notion in the unbounded-time case, but there appear to be differences when real-time or linear-time cellular automata are considered. The notion is then generalised to include probabilistic and alternating computations. Restricted nondeterminism classes are also defined and studied, in an attempt to refine the power of nondeterminism.
4 citations
TL;DR: This paper constructs oracle classes under which the CA classes coincide, and builds a hierarchy of relativised CA complexity classes between rCA and CA, and study the dependencies between the classes in this hierarchy.
Abstract: Some of the fundamental problems concerning cellular automata (CA) are as follows: ― Are linear-time CA (lCA) more powerful than real-time CA (rCA)? ― Are nonlinear-time CA more powerful than linear-time CA? ― Does one-way communication reduce the power of a CA? These question have been open for a long time. In this paper, we address these questions with respect to tally languages in relativised worlds, interpreting timevarying CA (TVCA) as orale machines. We construct ― oracles with separate rCA from lCA and lCA from CA, ― oracle classes under which the CA classes coincide, and ― oracle which leave the CA classes unchanged. Further, with rCA and lCA at the base, we build a hierarchy of relativised CA complexity classes between rCA and CA, and study the dependencies between the classes in this hierarchy