On Apr 5, 6:04 pm, WM <mueck...@rz.fh-augsburg.de> wrote: > On 5 Apr., 12:08, William Hughes <wpihug...@gmail.com> wrote:
> > There is an infinite set of lines D > > such that any finite subset of D can be removed. > > What has to remain?
This depends on the finite subset removed. If the finite set removed is E then D\E has to remain. Note that whatever subset E is chosen the number of lines in D\E is infinite (but of course we do not know which lines are in D\E).
However, D cannot be removed without changing the union of the remaining lines.