[MITSardine]

I may be misunderstanding your argument, but if it's that of a simple offset, then only the one starting from 0 forms a monoid (a group without an inverse to each element). Though, of course, you could redefine the + operation...

[JadeNB]

> I may be misunderstanding your argument, but if it's that of a simple offset, then only the one starting from 0 forms a monoid (a group without an inverse to each element). Though, of course, you could redefine the + operation...

Yes, agreed, there is other algebraic structure that can tell the difference, but Peano arithmetic by itself cannot.