ABSTRACT
Remark 1 . (Notation as in Proposition 16.7.) When R is commutative and g = x — c with c G R, we can calculate r directly, by means of “substituting” c for x; since r is constant and q (c) = 0 ,
(1)
Although the reader might be willing to accept this Remark without further ado, let us be careful and justify the substitution we have just made, by proving
Actually the following more general result will also be useful (One re covers Lemma 2 by taking C = R and ψ = 1r ).
