Abstract
The renormalization group technique is applied to an isotropic Heisenbergy spin system with long-range interaction and a set of critical exponents are calculated. These exponents are expressed in terms of a potential parameter sigma . All critical exponents except beta , the magnetization exponent, depend on sigma . The anisotropy is considered and the related crossover exponent phi is evaluated. This later parameter turns out to be equal to gamma , the susceptibility exponent, as predicted by some authors.