The dichotomy spectrum approach for a global nonuniform asymptotic stability problem: Triangular case via uniformization

By considering the nonuniform exponential dichotomy spectrum, we introduce a global asymptotic nonuniform stability conjecture for nonautonomous differential systems, whose restriction to the autonomous case is related to the classical Markus--Yamabe Conjecture: we prove that the conjecture is verified for a family of triangular systems of nonautonomous differential equations satisfying boundedness assumptions. An essential tool to carry out the proof is a necessary and sufficient condition ensuring the property of nonuniform exponential dichotomy for upper block triangular linear differential systems. We also obtain some byproducts having interest on itself, such as, the diagonal significance property in terms on the above mentioned spectrum.