Abstract
The problem of finding small universal spiking neural P systems was recently investigated by Andrei Păun and Gheorghe Păun, for spiking neural P systems used as devices computing functions and as devices generating sets of numbers. For the first case, a universal spiking neural P system was produced by using 84 neurons for standard rules and using 49 neurons for extended rules. For spiking neural P systems used as generators of sets of numbers, a universal system with standard rules having 76 neurons, and one with extended rules having 50 neurons were obtained. In this paper, we continue the study of small universal spiking neural P systems and we improve in the number of neurons as follows. The small universal spiking neural P systems use 67 neurons for standard rules and 41 neurons for extended rules in the case of computing functions, and 63 neurons for standard rules and 41 neurons for extended rules in the case of generating sets of numbers.