Oscillation of first order neutral functional differential equations (Q1824756)

The author obtains some new sufficient conditions for oscillation of the following first order neutral functional differential equations \[ (x(t)+cx(t-\tau))'-\sum^{n}_{i=1}p_ ix(t-\tau_ i)=0,\quad t\geq t_ 0, \] and \[ (x(t)-cx(t-\tau))'+P(t)x(t-\sigma)=0,\quad t\geq t_ 0 \] where \(\tau,\sigma,\{\tau_ i\}^ n_{i=1}\) are positive delays, \(p_ i\in R^*_+\), and P(t) is periodic with period \(\tau\).