The multiplicative anomaly associated with the zeta-function regularized
determinant is computed for the Laplace-type operators L_1=-\lap+V_1 and
L_2=-\lap+V_2, with V1, V2 constant, in a D-dimensional compact smooth
manifold MD, making use of several results due to Wodzicki and by direct
calculations in some explicit examples. It is found that the multiplicative
anomaly is vanishing for D odd and for D=2. An application to the one-loop
effective potential of the O(2) self-interacting scalar model is outlined.Comment: LaTeX, 17 pages, 3 figures. Small corrections, two new formulas, and
an addition to the references. To appear in Commun. Math. Phy