  In this paper we provide sufficient conditions that ensure the monotonicity,
respectively the global injectivity of an operator. Further, some new
analytical conditions that assure the injectivity/univalence of a complex
function of one complex variable are obtained. We also show that some classical
results, such as Alexander-Noshiro-Warschawski and Wolff theorem or Mocanu
theorem, are easy consequences of our results.
