How could you write NCpq in terms of moving the negation inside the conditional and keeping the conditional?
The question got posed here originally by someone else. I can't post there at the moment, so I thought I'd put it here.
If the only primitive connectives are negation N, and the material conditional C (all other connectives such as conjunction K, come as abbreviations, e. g. Kpq abbreviates NCpNq), can you write a formula logically equivalent to NCpq which has C as its first symbol in Polish notation? If so, what does it look like? If not, why not?