We consider spiking neural P systems with spiking rules allowed to introduce
zero, one, or more spikes at the same time. The computing power of the obtained systems
is investigated, when considering them as number generating and as language generating
devices. In the first case, a simpler proof of universality is obtained (universality is already
known for the restricted rules), while in the latter case we find characterizations of finite
and recursively enumerable languages (without using any squeezing mechanism, as it was
necessary in the case of restricted rules). The relationships with regular languages are
also investigated. In the end of the paper, a tool-kit for computing (some) operations
with languages is provided.Ministerio de Eduación y Ciencia TIN2005-09345-C04-0
