We study the implications of model completeness a theory for effectiveness presentations models that theory. It is immediate computable $$\mathcal {A}$$ computably enumerable, complete theory, entire elementary diagram $$E(\mathcal {A})$$ must be decidable. prove indeed c.e. T if and only there uniform procedure succeeds in deciding from atomic $$\varDelta (\mathcal all countable T. Moreover, e...