The extendability of solutions
of ordinary differential equations is a fundamental and important property since the
analysis of stability and boundedness of solutions requires extendability. This paper
is concerned with the preservation of the extendability and uniqueness of
solutions under perturbations. In particular conditions on the right hand
side of ẋ= f(x) + h(t) are exhibited which guarantee the extendability of
solutions whenever the solutions of the unperturbed equation ẋ= f(x)
extend.