A practical gauge invariant regularization of the SO(10) grand unified model

It is shown that a simple modification of the dimensional regularization allows to compute in a consistent and gauge invariant way any diagram with less than four loops in the SO(10) unified model. The method applies also to the Standard Model generated by the symmetry breaking $SO(10) \to SU(3)\times SU(2)\times U(1)$. A gauge invariant regularization for arbitrary diagram is also described.