  The quark matter phase diagram is believed to contain two distinguished
points, lying on the boundary of the Quark-Gluon Plasma phase: a critical point
and a triple point. In the holographic ["AdS/QCD"] approach, the region of
relatively low chemical potentials around the phase transition near the
critical point may be described using generalizations of the Hawking-Page
transition. We propose that the \emph{other} QGP phase line, beginning at the
triple point and rising towards the region of extremely high temperatures and
chemical potentials, is described instead by a non-perturbative string effect
discovered by Seiberg and Witten. Using an assumed position for the critical
point, we are able to use this proposal to obtain a holographic lower bound on
the temperature of the triple point. Combined with Shuryak's upper bound on
this temperature, this leads to a rough estimate of the location of the triple
point, at a temperature of around 70 MeV, and a chemical potential of about
1100 MeV.
