NUL-natural deduction for ultrafilter logic
Christian Jacques Renterıa, Edward Hermann Hæusler, Paulo A. S. Veloso · PhilPapers (PhilPapers Foundation) · 2003
Ultrafllter logic is an extension of flrst order logic that uses a new quantifler to express a meaning of \almost all, that is, to express sentences like: \Almost all elements of our universe have the property P. Such a logic had previously been presented only in an axiomatic version. We give here a natural deduction version, which is correct, complete and normalizable.