  We study transport properties of clean suspended graphene at the Dirac point.
In the absence of the electron-electron interaction, the main contribution to
resistivity comes from interaction with flexural (out-of-plane deformation)
phonons. We find that the phonon-limited conductivity scales with the
temperature as $T^{-\eta}, $ where $\eta$ is the critical exponent (equal to
$\approx 0.7$ according to numerical studies) describing renormalization of the
flexural phonon correlation functions due to anharmonic coupling with the
in-plane phonons. The electron-electron interaction induces an additional
scattering mechanism and also affects the electron-phonon scattering by
screening the deformation potential. We demonstrate that the combined effect of
both interactions results in a conductivity that can be expressed as a
dimensionless function of two temperature-dependent dimensionless constants,
$G[T]$ and $G_e[T]$ which characterize the strength of electron-phonon and
electron-electron interaction, respectively. We also discuss the behavior of
conductivity away from the Dirac point as well as the role of the impurity
potential and compare our predictions with available experimental data.
