  Matrix Graph Grammars (MGG) is a novel approach to the study of graph
dynamics ([15]). In the present contribution we look at MGG as a formal grammar
and as a model of computation, which is a necessary step in the more ambitious
program of tackling complexity theory through MGG. We also study its relation
with other well-known models such as Turing machines (TM) and Boolean circuits
(BC) as well as non-determinism. As a side effect, all techniques available for
MGG can be applied to TMs and BCs.
