In article <firstname.lastname@example.org>, WM <email@example.com> wrote:
> On 14 Apr., 02:42, Virgil <vir...@ligriv.com> wrote: > > > The question was whether A was in C, which it is provably not. > > Wrong. A is provably in C, because "all" numbers that can be in a > union of FISONs are in a union of FISONs in C,
But C is the sequence of FISONs, not their union. The only things that are members of C are FISONs, none of which either is A or contains A as a member.
Thus A is not a member of C and A is not a subset of C, so that outside of Wolkenmuekenheim, A is not "in" C on any way.
That A is in the union of C as a set of sets or is the limit of X as a sequence of sets, is not at all the same thing, despite WM's false claims.