In article <email@example.com>, WM <firstname.lastname@example.org> wrote:
> On 9 Dez., 18:50, Zuhair <zaljo...@gmail.com> wrote: > > On Dec 9, 7:34 pm, fom <fomJ...@nyms.net> wrote: > > > > > "Is x a member of y?" is a purely yes or no question. > > > > > Only with respect to a well-construed universe of discourse. > > > > WRONG, a "consistent" theory in classical logic is just enough. > > > > With respect to real numbers we need not only the answer to the > question whether x is a real number, but we need trichotomy with > respect to every real number. Undefinable numbers cannot satisfy this > need.
Wm may need it, but if the issue is only whether something is or is not a real number, there are definitions of what is a real number that does need not establish its trichotomy with anything.
Trichotomy is a derived property not a definitional one of some definitions of the reals.