The correlations in classical multi-component ionic mixtures with spatial
dimension d≥2 are studied by using a restricted grand-canonical ensemble
and the associated hierarchy equations for the correlation functions. Sum rules
for the first few moments of the two-particle correlation function are derived
and their dependence on d is established. By varying d continuously near
d=2 it is shown how the sum rules for the two-dimensional mixture are related
to those for mixtures at higher d.Comment: 19 page