Oscillation criteria for nonlinear differential systems with general deviating of mixed type (Q810245)

The following system with deviating arguments of mixed type \[ (1)\quad \dot y_ i=p_ i(t)y_{i+1}(h_{i+1}(t)),\quad i=1,...,n-1,\quad \dot y_ n=\pm \sum^{N}_{m=1}a_ m(t)f_ m(y_ 1(g_ m(t)) \] is considered. Functions at the right-hand side are supposed to be continuous on \([0,\infty)\). A solution of (1) is said to be the proper one if it is of class \(C^ 1([T_ y,\infty))\) and sup\(\{\sum^{n}_{i=1}| y_ i(t)|\), \(t\geq T\}>0\) for any \(T\geq T_ y\). The author studies the oscillatory properties of proper solutions of the system (1).