Re: Cardinality of Set of Computable Numbers?

From: George Greene (greeneg_at_greeneg-cs.cs.unc.edu)
Date: 12/30/03 

Date: 30 Dec 2003 13:13:56 -0500

"Russell Easterly" <logiclab@comcast.net> writes:
 : > > Since S is countable there is a function, f(),
 : > > that maps S to the natural numbers.
 : > > Using f() to order S, define a diagonal number, d.
 : > > d is a computable number not in S.
 : >
 : > Why is that? Can you exhibit a Turing machine to compute d?
 :
 : Good question. I need to define what computable means.

No, you need to define what NUMBER means.