Dual symmetries and universality of the critical behavior of a disordered ising ferromagnet

The critical behavior of a d-dimensional random Ising ferromagnet described in the critical region by the Ginzburg-Landau model with a random temperature has been considered. The critical temperature dependences of thermodynamic quantities, the equation of state, and the spin correlation function at the Curie point have been calculated by the renormalization group method. The most profound questions of the theory of impurity ferromagnets are the problem of universality and the role of the Griffiths singularities.