  The standard demand for the quantum partition function to be invariant under
the renormalization group transformation results in a general class of exact
renormalization group equations, different in the form of the kernel. Physical
quantities should not be sensitive to the particular choice of the kernel. Such
scheme independence is elegantly illustrated in the scalar case by showing
that, even with a general kernel, the one-loop beta function may be expressed
only in terms of the effective action vertices, and in this way the universal
result is recovered.
