The relationships existing between MP graphs, metabolic P systems, and
ODE systems are investigated. Formal results show that every MP system, once derived
by its MP graph, results in an ODE system whose solution equals, in the limit, the solution
obtained by a non-cooperative MP system that is ODE equivalent to the original one.
The freedom of choice of the ODE equivalent from the original MP system resembles the
same freedom which is left in the choice and optimization of a numerical scheme while
computing the solution of an ODE system.
