Considering a kind of neutral delay differential equations, a sufficient condition for the oscillation of all solutions of neutral delay differential equation in critical state is obtained.
讨论了一类中立型时滞微分方程所有解的振动性，获得了临界状态下该方程所有解振动的一个充分条件。
2
This paper deals with the existence and nonexistence of solutions for a critical semilinear polyharmonic equation with the second boundary and with a non-negative perturbation.
讨论了带非负扰动并具有第二类边值的临界非齐次多重调和方程的多解存在性和非存在性。
3
This paper deals with the existence and nonexistence of solutions for a critical semilinear polyharmonic equation with a non-negative perturbation.