FOM: Cantor's theorem of little interest in constructive math

Ayan amah8857 at
Wed Feb 14 14:11:08 EST 2001

At 07:54 PM 2/14/01, Kanovei wrote:
>One easily obtains LM but not Borel subset of R using axiom of

Can you please explain the "construction" a little bit, or point me to the 
right direction.

>If AC is not permitted the notion of Borel set needs to
>be adjusted (otherwise all sets can be Borel).

I don't understand this can you please explain, not permitting axiom of 
choice and working in a model where axiom of choice is false can be very 
different conceptually, of course I am guessing here.


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