  We study the properties of input-consuming derivations of moded logic
programs. Input-consuming derivations can be used to model the behavior of
logic programs using dynamic scheduling and employing constructs such as delay
declarations.
  We consider the class of nicely-moded programs and queries. We show that for
these programs a weak version of the well-known switching lemma holds also for
input-consuming derivations. Furthermore, we show that, under suitable
conditions, there exists an algebraic characterization of termination of
input-consuming derivations.
