Since the ab-functions of p are again bi-polar propositions, we can form ab-functions of them, & so on. In this way a series of propositions will arise, in which in general the symbolizing facts will be the same in several members. If now we find an ab-function of such a kind that by repeated application of it every ab-function can be generated, then we can
introduce
define
the totality of ab-functions as the totality of those that are generated by application of this function. Such a function is ~p ⌵ ~q.


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