On May 13, 2:50 am, kcrisman <[email protected]> wrote:
> On May 12, 8:39 pm, Fredrik Johansson <[email protected]>
> wrote:
>
> > On May 12, 11:19 pm, kcrisman <[email protected]> wrote:
>
> > > This should, in theory, give a plot of li(20^z) along the critical
> > > line of the Riemann zeta function.  Unfortunately, as you will see if
> > > you plot this, it succeeds until it hits a branch cut (I assume), and
> > > does not look so nice, not to mention missing the actual interesting
> > > behavior.
>
> > You probably want ei(log(20)*z), not li(20^z).
>
> Bingo!     Looks so beautiful.   Thank you very much.
>
> Wikipedia says as much, of course, but just the equivalence.    Is
> there an easy explanation for why one seems to have this branch
> phenomenon and the other doesn't?

Sure. li(z) is ei(log(z)) by definition. It's just a case of z*log(b)
having simpler branch structure than log(b^z) (since b^z is a periodic
function of z).

Fredrik

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