Abstract
This paper investigates the presence of oscillating solutions in time-varying
difference equations even in the case when there exist parametrical errors
(i.e., errors in the sequences defining their coefficients) and/or unmodeled dynamics,
namely, the current order is unknown and greater than the nominal known
order. The formulation is related to the concepts of conjugacy, disconjugacy,
positivity, and generalized zeros and general conditions of oscillation are obtained
both over particular intervals and for the whole solution. Some results concerned with
the presence of stable oscillations are also presented.