  We present an analytic calculation of the conductivity of pure graphene as a
function of frequency $\omega $, wave-vector $k$, and temperature for the range
where the energies related to all these parameters are small in comparison with
the band parameter $\gamma =3$ eV. The simple asymptotic expressions are given
in various limiting cases. For instance, the conductivity for $kv_{0}\ll T\ll
\omega $ is equal to $\sigma (\omega, k)=e^{2}/4\hbar $ and independent of the
band structure parameters $\gamma $ and $v_{0}$. Our results are also used to
explain the known dependence of the graphite conductivity on temperature and
pressure.
