Substitution

We will show how potential quasi-realizers convert to potential realizers in the next section. As we have already said, substitutions play a critical role. Much of what we need was discussed in Section 2.5, and this should be reviewed now. But we also need a few more technical items concerning substitution, peculiar to the problem at hand. In the next section we give an algorithm for converting potential quasi-realizers to realizers. Using implication as representative of the propositional cases of the algorithm, for A → B we will have substitutions