  In the present work the problem of distinguishing between essential and
spurious (i.e., absorbable) constants contained in a metric tensor field in a
Riemannian geometry is considered. The contribution of the study is the
presentation of a sufficient and necessary criterion, in terms of a covariant
statement, which enables one to determine whether a constant is essential or
not. It turns out that the problem of characterization is reduced to that of
solving a system of partial differential equations of the first order. In any
case, the metric tensor field is assumed to be smooth with respect to the
constant to be tested. It should be stressed that the entire analysis is purely
of local character.
