The divergence of the curvature function permits the definition of critical exponents γ γ , ν ν as | F ( k 0 , M ) | ∝ ∝ | M − − M c | − − γ γ , ξ ξ ∝ ∝ | M − − M c | − − ν ν . The conservation of the topological invariant C = c o n s t . , as the transition is approached from one side or the other, yields a scaling law that constraints the exponents γ γ = D ν ν , where D is the dimensionality of the problem. These exponents serve to classify topological phase transitions into different universality classes.