I need an example of a total ordering of the Natural numbers, that is not a well-ordering. So the classic "less than or equal to" doesn't work in this case since it is well-ordered.
I've been wracking my brain for hours but I can't just conjure up a relation. Is there a relatively simple one I'm forgetting?
How about:$$\ldots,7,5,3,1,0,2,4,6,\ldots$$
Or even simpler, just turn $\Bbb N$ around!
Added: To make that last idea more precise, define a relation $\preceq$ on $\Bbb N$ by $m\preceq n$ if and only if $n\le m$. Then check that $\preceq$ is a linear order on $\Bbb N$ that is not a well-order. (The last is clear, since for any $n\in\Bbb N$, $n+1\preceq n$, and therefore $\Bbb N$ has no $\preceq$-least element.)