 Together with  Theorem 2.3,  Theorem 3.1 and  Theorem 3.2  codify the basic properties of a model of computation which make it suitable for the development of a general theory of computability. In  Section 2  such a model has been defined in the form of the partial recursive functions. But as was discussed briefly at the end of  Section 2.2.2,  versions of these results may also be obtained for the other models of computation discussed in  Section 1.6.  This licenses the freer usage of computer-based analogies and other appeals to Church’s Thesis employed in most contemporary treatments of computability theory which will also be judiciously employed in the remainder of this entry.