We investigate the possibility of natural extensions of addition and multiplication of natural numbers to subsets of their Stone-Cech compactification betaN. We give a necessary and sufficient condition for a subset of betaN to be a supersemiring of N. In particular we characterize the ultrafilters contained in such semirings.
Ultrafilter semirings and nonstandard submodels of the Stone-Cech compactification of the natural numbers
DI NASSO, MAURO;FORTI, MARCO
2005-01-01
Abstract
We investigate the possibility of natural extensions of addition and multiplication of natural numbers to subsets of their Stone-Cech compactification betaN. We give a necessary and sufficient condition for a subset of betaN to be a supersemiring of N. In particular we characterize the ultrafilters contained in such semirings.File in questo prodotto:
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