[JadeNB]

> commonly denoted as N_0 and N_1

Oh my, it had never occurred to me that one could disagree, not just about whether the natural numbers include 0 or don't, but also about how to denote "natural numbers with 0" and "natural numbers without." Personally, I'm a fan of Z_{\ge 0} and Z_{> 0}, which are a little ugly but which any mathematician, regardless of their preferred conventions, can read and understand without further explanation.

[mathgeek]

Yep, lots of ways to denote these sets. It’s not a disagreement but rather a preference (although certainly some folks will gladly disagree).