Comparison theorems for focal points of systems of n-th order nonselfadjoint differential equations

Abstract

A comparison theorem will be given for focal points of x< n ) -^=o-^W*^ = 0> where n > 2,P are m X m matrices with continuous elements on[a.6],a > 0, and where no assumptions are made concerning the symmetry of any of the P nor the sign of the elements of P M .