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1. 7. 1987.
Sufficient conditions for oscillation and nonoscillation of neutral equations
Received July 9, 1986 Consider the neutral delay differential equation $x(r)-P(f)x(f-r)]+Q(t)x(r-0)-O, tat,, (1) where P, Q E C[ [ I~, co), (w + ] and T, D E Iw +. We obtain sutlicient conditions for all solutions of Eq. (1) to oscillate. Our conditions are “sharp” in the sense than when the coefficients P and Q are constants the conditions are also necessary. We also obtain sufficient conditions for Eq. (1) to have a nonoscillatory solution when P(r) is a constant in the interval