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No, it is the case. Look for the comment in the article, after passing to a subsequence if necessary. The ultrafilter produces the necessary subsequence for an
by btilly 1y ago
No, it is the case.
Look for the comment in the article, after passing to a subsequence if necessary. The ultrafilter produces the necessary subsequence for any question that you ask, and will do so in such a way as to produce logically consistent answers for any combination of questions that you choose.
That is why the ultrafilter axiom is a weak version of choice. Take the set of possible yes/no questions that we can ask as predicates, such that each answer shows up infinitely often. The ultrafilter results in an arbitrary yet consistent set of choices of yes/no for each predicate.
- JohnKemeny 1y agoOkay, yes, I see. But then it seems that O doesn't obey some very natural standard schools, and then what is it good for? O is a total order, but functions aren't in any way a total order, so what's the point?
- btilly 1y agoAnd now you see what I don't like about it!