  It is well known that for a regular stable potential of pair interaction and
a small value of activity one can define the corresponding Gibbs field (a
measure on the space of configurations of points in $\mathbb{R}^d$).
  In this paper we consider a converse problem. Namely, we show that for a
sufficiently small constant $\overline{\rho}_1$ and a sufficiently small
function $\overline{\rho}_2(x)$, $x \in \mathbb{R}^d$, that is equal to zero in
a neighborhood of the origin, there exist a hard core pair potential, and a
value of activity, such that $\overline{\rho}_1$ is the density and
$\overline{\rho}_2$ is the pair correlation function of the corresponding Gibbs
field.
