Disconjugacy and Comparison Theorems for Second-Order Linear Systems

Source abstract

Sufficient conditions for disconjugacy and disfocality are obtained for the second-order system $y'' + Ay = 0$, where A is an $n \times n$ matrix. Also proved are comparison theorems for disfocality through a generalization of the Riccati equation method originally used by Hille (Traps. Amer. Math. Soc., 64 (1948), pp. 234–252) for the case $n = 1$.