本文对满足条件1-4（或4＇）的一类具重特征的双曲拟微分算子（1）进行初步的讨论。

In this paper we will study the pseudo-differential operators P which satisfy conditions 1-4(or 4'). They constitute a class of hyperbolic operators with multi-characteristics.

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本文在一维情形下对拟可微函数的星核进行了讨论，证明了拟微分星-有界等价子类的存在性；

In this paper, the star-kernel of a quasi-differentiable function in one-dimensional space is studied.

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建立了具泛函变元的拟线性偏微分系统解振动的充分条件。

Sufficient conditions are established for the oscillation of systems of second order partial differential equations with functional arguments.

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