I'm sure that you have read a lot more math papers than have I, but I can tell you that I have _never_ seen a math or computer science paper in which |N excluded 0. At least in the CS community, if you want the positives only, you need to say |N^+ (i.e., |N superscript +). Re "unsigned": actually in C/C++, "unsigned" means modular arithmetic relative to the word size, so "unsigned 5" (written "5U"), means 5 modulo 2^n (n=8, 16, 32, 64, etc.). At 01:40 PM 10/31/03 -0500, John Conway wrote:
On Fri, 31 Oct 2003, Henry Baker wrote:
Whatever happened to |N, as in "Natural" numbers? Call it a "natural".
There are two objections to this. The first is that my request was for a word meaning "at least zero". This won't be applied only to integers. The second is that there are still two schools of thought about "natural number", the "inclusivists" (like me) who count 0 as one, and the "exclusivists" who don't. Until the great day when the inclusivists win, it remains ambiguous.
Computer languages such as Ada have had to deal with this same problem -- that of naming the set of non-negative numbers.
I think that C/C++ call these "unsigned ints", or unsigned's, for short.
Those are slightly different again, since the "unsigned integer 5" is really the quotient concept {5, -5} rather than the sub-concept +5.
John Conway