A. Procacci et B. Scoppola, The gas phase of continuous systems of hard spheres interacting via n-bodypotential, COMM MATH P, 211(2), 2000, pp. 487-496
We show that a system of classical continuous hard spheres interacting thro
ugh a general n body potential satisfying suitable integrability conditions
, admits a high temperature-low activity gas phase. We find explicitly a co
ndition on the activity lambda and the inverse temperature beta which ensur
es that the Mayer series for the pressure is absolutely convergent uniforml
y in the volume.