Exact treatment of operator difference equations with nonconstant and noncommutative coefficients.

We study a homogeneous linear second-order difference equation with nonconstant and noncommuting operator coefficients in a vector space. We build its exact resolutive formula consisting of the explicit noniterative expression of a generic term of the unknown sequence of vectors. Some nontrivial applications are reported in order to show the usefulness and the broad applicability of the result. [ABSTRACT FROM AUTHOR]