Exact bounds for exponential dichotomy roughness. III: Semistrong dichotomy (Q1176511)

[For part II see the above review.] Consider the linear system (1) \(x'=A(t)x\) and its perturbation (2) \(x'=[A(t)+B(t)]x\). In an earlier paper [J. Differ. Equations 71, 63-71 (1988; Zbl 0651.34051)] the author obtained exact bounds for exponential dichotomy roughness by suitably restricting the perturbation term \(B(t)\). In this paper, the author shows that orthogonality of unperturbed subspaces and other restrictions on (2) may be removed.