On a full spectrum condition for 2-dimensional linear quasi-periodic systems (Q912259)

Consider the system \(\dot x=(\Lambda +\epsilon A(t))x\) where \(x\in C^ 2\), \(\Lambda =\left[ \begin{matrix} 0\quad 1\\ 0\quad 0\end{matrix} \right]\) and A(t) is an almost periodic function. If the number of characteristic exponents of the differential equation equals its dimension, then the equation is said to have full spectrum. Sufficient conditions on A(t) are obtained for the equation to have full spectrum.