In article <email@example.com>, WM <firstname.lastname@example.org> wrote:
> What is the difference between E (the set of numbers of lines that can > be removed without changing the union of the remaining lines) and the > set D (the set of numbers of all lines of the list > 1 > 1, 2 > 1, 2, 3 > ... > ) > ? > > By "difference" I mean something that can be substantiated in > mathematics and communicated by electrical signals in the internet, > not only your feeling that something unnameable should remain there.
Where D is now the set of all line numbers.
E is given to be a subset of D, so D\E must be an infinite set of lines.
Equivalently, E must be a co-infinite subset of D.
Similarly, if F is the set of all FISONs, so its union is |N, then for E to be a subset of F such that the union of F\E equals |N, it is a NASC that F\E be infinite. --